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This study presents the exploration of sequence‐defined polyurethanes (PUs) as a new class of heteropolymers capable of precise conformational control. Utilizing molecular dynamics simulations, the folding behavior of polyurethane chains is investigated of varying lengths (11, 20, and 50 monomers) in both vacuum and aqueous environments. The simulations reveal that the heterogeneous chains systematically refold to approach the designed target structures better than non‐designed chains or chains with artificially disrupted hydrogen‐bond networks. The subsequent synthesis of an optimized 11‐mer sequence (P1) is achieved through solid‐phase chemistry, with thorough characterization via NMR, MS, and SEC confirming the accuracy of the predicted sequence and its controlled chain length. Solubility tests showed favorable results across multiple solvents, highlighting the versatility of the designed polymer. This research underscores the potential of sequence‐defined polyurethanes to emulate the structural and functional attributes of biological macromolecules, opening new pathways for their application in catalysis, drug delivery, and advanced material design. The findings illustrate a promising direction for the development of synthetic polymers with tailored properties, emphasizing the transformative impact of sequence control in polymer chemistry. [ABSTRACT FROM AUTHOR]

Background: The microbial landscape within termite guts varies across termite families. The gut microbiota of lower termites (LT) is dominated by cellulolytic flagellates that sequester wood particles in their digestive vacuoles, whereas in the flagellate-free higher termites (HT), cellulolytic activity has been attributed to fiber-associated bacteria. However, little is known about the role of individual lineages in fiber digestion, particularly in LT. Results: We investigated the lignocellulolytic potential of 2223 metagenome-assembled genomes (MAGs) recovered from the gut metagenomes of 51 termite species. In the flagellate-dependent LT, cellulolytic enzymes are restricted to MAGs of Bacteroidota (Dysgonomonadaceae, Tannerellaceae, Bacteroidaceae, Azobacteroidaceae) and Spirochaetota (Breznakiellaceae) and reflect a specialization on cellodextrins, whereas their hemicellulolytic arsenal features activities on xylans and diverse heteropolymers. By contrast, the MAGs derived from flagellate-free HT possess a comprehensive arsenal of exo- and endoglucanases that resembles that of termite gut flagellates, underlining that Fibrobacterota and Spirochaetota occupy the cellulolytic niche that became vacant after the loss of the flagellates. Furthermore, we detected directly or indirectly oxygen-dependent enzymes that oxidize cellulose or modify lignin in MAGs of Pseudomonadota (Burkholderiales, Pseudomonadales) and Actinomycetota (Actinomycetales, Mycobacteriales), representing lineages located at the hindgut wall. Conclusions: The results of this study refine our concept of symbiotic digestion of lignocellulose in termite guts, emphasizing the differential roles of specific bacterial lineages in both flagellate-dependent and flagellate-independent breakdown of cellulose and hemicelluloses, as well as a so far unappreciated role of oxygen in the depolymerization of plant fiber and lignin in the microoxic periphery during gut passage in HT. Ak1UNwnHwhcNN-Fj12kHob Video Abstract [ABSTRACT FROM AUTHOR]

Digitally‐encoded poly(phosphodiesters) (d‐PPDE) with highly complex primary structures are evaluated for layer‐by‐layer (LbL) assembly. To be easily decoded by mass spectrometry (MS), these digital polymers contain many different monomers: 2 coding units allowing binary encryption, 1 cleavable spacer allowing controlled MS fragmentation, and 3 mass tags allowing fragment identification. These complex heteropolymers are therefore composed of 6 different motifs. Despite this strong sequence heterogeneity, it is found that they enable a highly controlled LbL film formation. For instance, a regular growth is observed when alternating the deposition of negatively‐charged d‐PPDE and positively‐charged poly(allyl amine hydrochloride) (PAH). Yet, in this approach, the interdistance between consecutive coded d‐PPDE layers remains relatively small, which may be an issue for data storage applications, especially for the selective decoding of the stored information. Using poly(sodium 4‐styrene sulfonate) (PSS) as an intermediate non‐coded polyanion, it is shown that a controlled interdistance between d‐PPDE layers can be easily achieved, while still maintaining a regular LbL growth. Last but not least, it is found in this work that d‐PPDE of relatively small molecular weight (i.e., significantly smaller than those of PAH and PSS) still enables a controlled LbL assembly. [ABSTRACT FROM AUTHOR]

Rhodococcus rhodochrous strain М8 is a platform for development of the biotechnologies for biocatalytic production of acrylic monomers, the raw material for synthesis of acrylic heteropolymers. A genetic system for investigation of the cobalt-dependent transcription of nitrile hydratase genes in this strain was constructed, based on the reporter gene of the metal-independent acylamidase from Rhodococcus qingshengii TA37. The cobalt-regulated promoter was shown to be located at a significant distance (~0.5 kb) from nitrile hydratase genes. Excision of the region between the promoter and the nitrile hydratase genes decreased significantly both the promoter activity and the degree of regulation by cobalt. Our results improve the possibilities for rational design of regulated expression cassettes using the promoter of nitrile hydratase genes in Rhodococcus, and for further development of biocatalysts based on these bacteria. [ABSTRACT FROM AUTHOR]

Septins are a family of membrane-associated cytoskeletal guanine-nucleotide binding proteins that play crucial roles in various cellular processes, such as cell division, phagocytosis, and organelle fission. Despite their importance, the evolutionary origins and ancestral function of septins remain unclear. In opisthokonts, septins form five distinct groups of orthologs, with subunits from multiple groups assembling into heteropolymers, thus supporting their diverse molecular functions. Recent studies have revealed that septins are also conserved in algae and protists, indicating an ancient origin from the last eukaryotic common ancestor. However, the phylogenetic relationships among septins across eukaryotes remained unclear. Here, we expanded the list of nonopisthokont septins, including previously unrecognized septins from glaucophyte algae. Constructing a rooted phylogenetic tree of 254 total septins, we observed a bifurcation between the major non-opisthokont and opisthokont septin clades. Within the non-opisthokont septins, we identified three major subclades: Group 6 representing chlorophyte green algae (6A mostly for species with single septins, 6B for species with multiple septins), Group 7 representing algae in chlorophytes, heterokonts, haptophytes, chrysophytes, and rhodophytes, and Group 8 representing ciliates. Glaucophyte and some ciliate septins formed orphan lineages in-between all other septins and the outgroup. Combining ancestral-sequence reconstruction and AlphaFold predictions, we tracked the structural evolution of septins across eukaryotes. In the GTPase domain, we identified a conserved GAP-like arginine finger within the G-interface of at least one septin in most algal and ciliate species. This residue is required for homodimerization of the single Chlamydomonas septin, and its loss coincided with septin duplication events in various lineages. The loss of the arginine finger is often accompanied by the emergence of the a0 helix, a known NC-interface interaction motif, potentially signifying the diversification of septinseptin interaction mechanisms from homo-dimerization to heterooligomerization. Lastly, we found amphipathic helices in all septin groups, suggesting that membrane binding is an ancestral trait. Coiled-coil domains were also broadly distributed, while transmembrane domains were found in some septins in Group 6A and 7. In summary, this study advances our understanding of septin distribution and phylogenetic groupings, shedding light on their ancestral features, potential function, and early evolution. [ABSTRACT FROM AUTHOR]

Background: Direct RNA sequencing (dRNA-seq) on the Oxford Nanopore Technologies (ONT) platforms can produce reads covering up to full-length gene transcripts, while containing decipherable information about RNA base modifications and poly-A tail lengths. Although many published studies have been expanding the potential of dRNA-seq, its sequencing accuracy and error patterns remain understudied. Results: We present the first comprehensive evaluation of sequencing accuracy and characterisation of systematic errors in dRNA-seq data from diverse organisms and synthetic in vitro transcribed RNAs. We found that for sequencing kits SQK-RNA001 and SQK-RNA002, the median read accuracy ranged from 87% to 92% across species, and deletions significantly outnumbered mismatches and insertions. Due to their high abundance in the transcriptome, heteropolymers and short homopolymers were the major contributors to the overall sequencing errors. We also observed systematic biases across all species at the levels of single nucleotides and motifs. In general, cytosine/uracil-rich regions were more likely to be erroneous than guanines and adenines. By examining raw signal data, we identified the underlying signal-level features potentially associated with the error patterns and their dependency on sequence contexts. While read quality scores can be used to approximate error rates at base and read levels, failure to detect DNA adapters may be a source of errors and data loss. By comparing distinct basecallers, we reason that some sequencing errors are attributable to signal insufficiency rather than algorithmic (basecalling) artefacts. Lastly, we generated dRNA-seq data using the latest SQK-RNA004 sequencing kit released at the end of 2023 and found that although the overall read accuracy increased, the systematic errors remain largely identical compared to the previous kits. Conclusions: As the first systematic investigation of dRNA-seq errors, this study offers a comprehensive overview of reproducible error patterns across diverse datasets, identifies potential signal-level insufficiency, and lays the foundation for error correction methods. [ABSTRACT FROM AUTHOR]

This article explores the impact of different types of mycorrhizal symbiosis on the chemical composition of roots and leaves in temperate woody species. The study found that plants associated with ectomycorrhizal (EcM) fungi had slower decomposition rates and exhibited chemical traits that suppress decomposition compared to plants associated with arbuscular mycorrhizal (AM) fungi. The study also suggests that mycorrhizal associations can influence plant defense responses and the abundance of defense-related phenolic compounds. Another study conducted at the University of Minnesota found that different plant-fungus combinations had significant effects on plant growth and chemical composition. However, the results may not be generalizable to other environmental settings. Another study found that mycorrhizal colonization generally improved plant growth and increased nitrogen content, but the effects on lignin and condensed tannins varied depending on the plant species and type of mycorrhizal fungi. The study also found that mycorrhizal colonization had different effects on lignin molecular composition in gymnosperms and angiosperms. Overall, mycorrhizal colonization can influence the chemical traits and lignin composition of plants, but more research is needed to understand the ecological implications. [Extracted from the article]

We investigate the translocation of a semiflexible polymer through extended patterned pores using Langevin dynamics simulations, specifically focusing on the influence of a time-dependent driving force. Our findings reveal that, akin to its flexible counterpart, a rigid chain-like molecule translocates faster when subjected to an oscillating force than a constant force of equivalent average magnitude. The enhanced translocation is strongly correlated with the stiffness of the polymer and the stickiness of the pores. The arrangement of the pores plays a pivotal role in translocation dynamics, deeply influenced by the interplay between polymer stiffness and pore-polymer interactions. For heterogeneous polymers with periodically varying stiffness, the oscillating force introduces significant variations in the translocation time distributions based on segment sizes and orientations. On the basis of these insights, we propose a sequencing approach that harnesses distinct pore surface properties that are capable of accurately predicting sequences in heteropolymers with diverse bending rigidities. [ABSTRACT FROM AUTHOR]

Nickel diselenide (NiSe2), which has a high theoretical capacity, has attracted considerable attention as a promising anode material for sodium-ion batteries (SIBs). Nevertheless, the intrinsically low conductivity, large volume variation, and significant aggregation of NiSe2 during sodiation/desodiation remain significant obstacles to its application. Herein, we report flower-like Fe-doped NiSe2/C hybrid spheres (denoted as Fe-NiSe2/C) fabricated by a glucose intercalation strategy for efficient sodium storage. These Fe-NiSe2 /C hybrid spheres are composed of thin porous carbon nanosheets decorated with Fe-NiSe2 nanoparticles. In situ introduced carbon nanosheets derived from intercalated glucose accompanied by moderate Fe doping in NiSe2 nanoparticles can provide accelerated ion/electron transfer kinetics through fast ion channels in the flower-like architecture and intimately contacted interfaces between NiSe2 and carbon nanosheets as well as maintain structural integrity by alleviating volume variation. Consequently, the optimal anode of the Fe-NiSe2 /C hybrid spheres delivered a high discharge capacity of 415 mAh g-1 at 0.5 A g-1, outstanding rate capability (243 mAh g-1 at 5 A g-1), and significantly enhanced cycling stability (388 mAh g-1 at 1 A g-1 over 200 cycles). This work offers an efficient and valuable strategy for realizing tailored heteroatom doping in transition metal selenides, accompanied by an in situ combination of conductive carbonaceous networks for advanced alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

The human polysialyltransferases ST8Sia II and ST8Sia IV catalyze the transfer of several Neu5Ac residues onto glycoproteins forming homopolymers with essential roles during different physiological processes. In salmonids, heterogeneous set of sialic acids polymers have been described in ovary and on eggs cell surface and three genes st8sia4, st8sia2-r1 and st8sia2-r2 were identified that could be implicated in these heteropolymers. The three polysialyltransferases from the salmonid Coregonus maraena were cloned, recombinantly expressed in HEK293 cells and the ST8Sia IV was biochemically characterized. The MicroPlate Sialyltransferase Assay and the non-natural donor substrate CMP-SiaNAl were used to demonstrate enzyme activity and optimize polysialylation reactions. Polysialylation was also carried out with natural donor substrates CMP-Neu5Ac, CMP-Neu5Gc and CMP-Kdn in cell-free and cell-based assays and structural analyses of polysialylated products using the anti-polySia monoclonal antibody 735 and endoneuraminidase N and HPLC approaches. Our data highlighted distinct specificities of human and salmonid polysialyltransferases with notable differences in donor substrates use and the capacity of fish enzymes to generate heteropolymers. This study further suggested an evolution of the biological functions of polySia. C. maraena ST8Sia IV of particular interest to modify glycoproteins with a variety of polySia chains. [ABSTRACT FROM AUTHOR]

Evolution in time-varying environments naturally leads to adaptable biological systems that can easily switch functionalities. Advances in the synthesis of environmentally responsive materials therefore open up the possibility of creating a wide range of synthetic materials which can also be trained for adaptability. We consider highdimensional inverse problems for materials where any particular functionality can be realized by numerous equivalent choices of design parameters. By periodically switching targets in a given design algorithm, we can teach a material to perform incompatible functionalities with minimal changes in design parameters. We exhibit this learning strategy for adaptability in two simulated settings: elastic networks that are designed to switch deformation modes with minimal bond changes and heteropolymers whose folding pathway selections are controlled by a minimal set of monomer affinities. The resulting designs can reveal physical principles, such as nucleation-controlled folding, that enable such adaptability. [ABSTRACT FROM AUTHOR]

Bacillus cereus is a gram-positive bacterium belonging to the Bacillus genus. It is widespread in several ecological niches and has interesting genetic and metabolic properties that allow the production of polyhydroxyalkanoates (PHAs) with suitable physicochemical properties for several biomedical applications. Despite the numerous publications over the last 20 years dedicated to reporting the isolation of this bacterial strain and its PHA productive capacity, more information on several important points (such as biosecurity controls, the use of agro-industrial by-products as substrates for PHAs production, genomic mining strategies, fermentative studies at pilot scale, the propose of novel PHA-recovery protocols based on techno-economic and ecological studies, and certifications of the biopolymer obtained) is still needed before B. cereus could be proposed as a model for the industrial production of these biopolymers. Hence, this review discusses the properties of B. cereus as a potential PHA-producing model and highlights the areas of opportunity for future research on this bacterium. [Display omitted] • B. cereus is a promising alternative for polyhydroxyalkanoates (PHAs) production. • Interesting genetic and metabolic properties. • Ability to produce heteropolymers from a sole carbon source. • PHAs with suitable properties for biomedical applications. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis (Mtb), perhaps more than any other organism, is intrinsically appealing to chemical biologists. Not only does the cell envelope feature one of the most complex heteropolymers found in nature 1 but many of the interactions between Mtb and its primary host (we humans) rely on lipid and not protein mediators. 2,3 Many of the complex lipids, glycolipids, and carbohydrates biosynthesized by the bacterium still have unknown functions, and the complexity of the pathological processes by which tuberculosis (TB) disease progress offers many opportunities for these molecules to influence the human response. Because of the importance of TB in global public health, chemical biologists have applied a wide-ranging array of techniques to better understand the disease and improve interventions. [Display omitted] Mycobacterium tuberculosis is the largest single infectious cause of death globally, and the community of chemical biologists has made significant strides in providing new tools and insights into this important pathogen. Finin et al. highlight progress made over the past ten years by this community. [ABSTRACT FROM AUTHOR]

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Four model polymers, representing (i) amorphous homopolymers (Kollidon K30, K30), (ii) amorphous heteropolymers (Kollidon VA64, KVA), (iii) semi-crystalline homopolymers (Parteck MXP, PXP), and (iv) semi-crystalline heteropolymers (Kollicoat IR, KIR), were examined for their effectiveness in creating posaconazole-based amorphous solid dispersions (ASDs). Posaconazole (POS) is a triazole antifungal drug that has activity against Candida and Aspergillus species, belonging to class II of the biopharmaceutics classification system (BCS). This means that this active pharmaceutical ingredient (API) is characterized by solubility-limited bioavailability. Thus, one of the aims of its formulation as an ASD was to improve its aqueous solubility. Investigations were performed into how polymers affected the following characteristics: melting point depression of the API, miscibility and homogeneity with POS, improvement of the amorphous API's physical stability, melt viscosity (and associated with it, drug loading), extrudability, API content in the extrudate, long term physical stability of the amorphous POS in the binary drug–polymer system (in the form of the extrudate), solubility, and dissolution rate of hot melt extrusion (HME) systems. The obtained results led us to conclude that the physical stability of the POS-based system increases with the increasing amorphousness of the employed excipient. Copolymers, compared to homopolymers, display greater homogeneity of the investigated composition. However, the enhancement in aqueous solubility was significantly higher after utilizing the homopolymeric, compared to the copolymeric, excipients. Considering all of the investigated parameters, the most effective additive in the formation of a POS-based ASD is an amorphous homopolymer—K30. [ABSTRACT FROM AUTHOR]

Membrane polymers are a promising technology for use in many challenging gas separation applications. The techniques of computer‐aided molecular design can be used to search through the massive molecular space of heteropolymers and develop a set of likely candidate repeat units matching specific physical property targets. However, reasonably accurate property prediction algorithms are needed, but these algorithms must be very fast in order to be combined with an optimization framework. Artificial neural networks (ANNs), a branch of machine learning, are applied in this work to predict the physical properties of polymers. All of the physical properties investigated were found to be predicted by ANNs with R2 scores exceeding 0.82. [ABSTRACT FROM AUTHOR]

Achieving stable surface structures of metal catalysts is an extreme challenge for obtaining long-term durability and meeting industrial application requirements. We report a new class of metal catalyst, Pt-rich PtCu heteroatom subnanoclusters epitaxially grown on an octahedral PtCu alloy/Pt skin matrix (PtCu1.60), for the oxygen reduction reaction (ORR) in an acid electrolyte. The PtCu1.60/C exhibits an 8.9-fold enhanced mass activity (1.42 A·mgPt−1) over that of commercial Pt/C (0.16 A·mgPt−1). The PtCu1.60/C exhibits 140,000 cycles durability without activity decline and surface PtCu cluster stability owing to unique structure derived from the matrix and epitaxial growth pattern, which effectively prevents the agglomeration of clusters and loss of near-surface active sites. Structure characterization and theoretical calculations confirm that Pt-rich PtCu clusters favor ORR activity and thermodynamic stability. In room-temperature polymer electrolyte membrane fuel cells, the PtCu1.60/C shows enhanced performance and delivers a power density of 154.1/318.8 mW·cm−2 and 100 h/50 h durability without current density decay in an air/O2 feedstock. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction is a viable, economical, and sustainable method to transform atmospheric CO2 into carbon-based fuels and effectively reduce climate change and the energy crisis. Constructing robust catalysts through interface engineering is significant for electrocatalytic CO2 reduction (ECR) but remains a grand challenge. Herein, SnO2/Bi2O2CO3 heterojunction on N,S-codoped-carbon (SnO2/BOC@NSC) with efficient ECR performance was firstly constructed by a facile synthetic strategy. When the SnO2/BOC@NSC was utilized in ECR, it exhibits a large formic acid (HCOOH) partial current density (JHCOOH) of 86.7 mA·cm−2 at −1.2 V versus reversible hydrogen electrode (RHE) and maximum Faradaic efficiency (FE) of HCOOH (90.75% at −1.2 V versus RHE), respectively. Notably, the FEHCOOH of SnO2/BOC@NSC is higher than 90% in the flow cell and the JHCOOH of SnO2/BOC@NSC can achieve 200 mA·cm−2 at −0.8 V versus RHE to meet the requirements of industrialization level. The comparative experimental analysis and in-situ X-ray absorption fine structure reveal that the excellent ECR performance can be ascribed to the synergistic effect of SnO2/BOC heterojunction, which enhances the activation of CO2 molecules and improves electron transfer. This work provides an efficient SnO2-based heterojunction catalyst for effective formate production and offers a novel approach for the construction of new types of metal oxide heterostructures for other catalytic applications. [ABSTRACT FROM AUTHOR]

Dual heteroatom-doped carbons have attracted widespread research attention as catalysts in the field of energy storage and conversion due to their unique electronic structures and chemical tunability. In particular, boron and nitrogen co-doped carbon (B,N@C) has shown great potential for photo/electrocatalytic applications. However, more needs to be done for rational designing and regulating the structure of these materials to improve their catalytic performance. Herein, monodispersed hierarchical porous B,N@C nanocages were fabricated by pyrolyzing zeolite imidazole framework (ZIF) which was treated with ammonia borane or boric acid via an integrated double-solvent impregnation and nanocofined-etching method. The treated ZIF-8 provided an essential structural template to achieve B, N co-doped hierarchical structures with micro/meso/macro multimodal pore size distributions. The resultant B,N@C nanocages displayed high catalytic activities for electrochemical oxygen reduction reaction (ORR) in alkaline media, outperforming most carbon-based catalysts, particularly from the perspective of the half-wave potentials. Such high catalytic performance is due to the enhanced activity by the coexistence of B and N and the mass transfer promoted by the unique hierarchical porous structure. [ABSTRACT FROM AUTHOR]

Biochar applications to soils may enhance soil quality, hydrological properties, and agronomic productivity. Modification of biochar by activation via introduction of heteroatoms at different pyrolysis conditions can alter physical and chemical characteristics, which may enhance soil properties, although the extent of this is unknown. The objective of this study was to investigate the impacts of pyrolysis temperature (400, 500, 600, and 700 °C) on activated (activated with methanesulfonic acid) and unactivated biochar produced from poultry litter to identify optimum production conditions for end use as a soil amendment. Physical, chemical, and surface properties of biochars were determined using wet chemistry and spectroscopic analyses. Results showed that activation with methanesulfonic acid increased biochars' oxygen content, while decreasing its point of zero charge and electrical conductivity. Conversion of raw poultry litter to activated and unactivated biochar increased concentration of P (3-fold), K (1.8-fold), Ca (3-fold), Mg (2.3-fold), and S (4.8-fold), with concentrations increasing with increasing temperatures (p < 0.05) except for C and N. Activated biochar had lower recovery of C and N, but greater water-holding capacity than unactivated biochar. Concentrations of NH4-N, NO3-N, and water-soluble P were greater in unactivated biochar (p < 0.05). Among all biochars, activated biochar produced at 400 °C had the lowest bulk density, total P, K, Ca, and Mg, and greatest water-holding capacity, water-soluble P, Ca, and Mg concentrations, thereby suggesting improved soil amendment characteristics and subsequent soil health under poultry litter biochars produced under these conditions. [ABSTRACT FROM AUTHOR]

Pyruvate kinase (PK) is one of the three rate-limiting enzymes of glycolysis, and it plays a pivotal role in energy metabolism. In this study, we have identified 10 PK genes from the rice genome. Initially, these genes were divided into two categories: cytoplasmic pyruvate kinase (PKc) and plastid pyruvate kinase (PKp). Then, an expression analysis revealed that OsPK1, OsPK3, OsPK4, OsPK6, and OsPK9 were highly expressed in grains. Moreover, PKs can form heteropolymers. In addition, it was found that ABA significantly regulates the expression of PK genes (OsPK1, OsPK4, OsPK9, and OsPK10) in rice. Intriguingly, all the genes were found to be substantially involved in the regulation of rice grain quality and yield. For example, the disruption of OsPK3, OsPK5, OsPK7, OsPK8, and OsPK10 and OsPK4, OsPK5, OsPK6, and OsPK10 decreased the 1000-grain weight and the seed setting rate, respectively. Further, the disruption of OsPK4, OsPK6, OsPK8, and OsPK10 through the CRISPR/Cas9 system showed an increase in the content of total starch and a decrease in protein content compared to the WT. Similarly, manipulations of the OsPK4, OsPK8, and OsPK10 genes increased the amylose content. Meanwhile, the grains of all CRISPR mutants and RNAi lines, except ospk6, showed a significant increase in the chalkiness rate compared to the wild type. Overall, this study characterizes the functions of all the genes of the PK gene family and shows their untapped potential to improve rice yield and quality traits. [ABSTRACT FROM AUTHOR]

High-performance aromatic heterochain polymers are engineering thermoplastics with exceptional mechanical and thermal properties that have attracted great interest in various areas ranging from aerospace to biomedicine. However, there have been a number of difficulties to 3D-print materials based on such polymers with new promising performance characteristics. Herein, a number of new photosensitive compositions (PSCs) based on high-performance polyetherimide (PEI) or polysulfone (PSU), reactive functional monomer (N , N -dimethylacrylamide) and oligomer (bisphenol A ethoxylate diacrylate) has been developed. It has been shown that the use of the developed PSCs allows the formation of 3D-structures with high printing resolution by LCD 3D-printing. Subsequent thermal post-curing of 3D-printed green-state samples at 250°С for 1 h led to the fabrication of materials with the highest tensile strength (up to 41.9 ± 3.1 MPa), glass transition temperature (141 °C) and thermal stability (above 350 °C). In addition, 3D-printed structures demonstrate high-temperature shape memory effect with shape fixity ratio > 99% and shape recovery ratio up to 97.1%. [Display omitted] • A composition based on PEI or PSU can be used for LCD 3D-printing. • The materials are characterized by a high tensile strength and thermal stability. • The 4D-printed structures possess a good shape memory performance at T rec = 171 °C. [ABSTRACT FROM AUTHOR]

Reduction of information entropy along with ever-increasing complexity is among the key signatures of life. Understanding the onset of such behavior in the early prebiotic world is essential for solving the problem of the origin of life. Here we study a general problem of heteropolymers capable of template-assisted ligation based on Watson-Crick-like hybridization. The system is driven off-equilibrium by cyclic changes in the environment. We model the dynamics of 2-mers, i.e., sequential pairs of specific monomers within the heteropolymer population. While the possible number of them is Z2 (where Z is the number of monomer types), we observe that most of the 2-mers get extinct, leaving no more than 2Z survivors. This leads to a dramatic reduction of the information entropy in the sequence space. Our numerical results are supported by a general mathematical analysis of the competition of growing polymers for constituent monomers. This natural-selection-like process ultimately results in a limited subset of polymer sequences. Importantly, the set of surviving sequences depends on initial concentrations of monomers and remains exponentially large (2L down from ZL for length L) in each of realizations. Thus, an inhomogeneity in initial conditions allows for a massively parallel search of the sequence space for biologically functional polymers, such as ribozymes. We also propose potential experimental implementations of our model in the contexts of either biopolymers or artificial nano-structures. [ABSTRACT FROM AUTHOR]

This work demonstrates the remodeling of single‐chain nanoparticles (SCNPs) upon a transition to organic solvent through molecular dynamics simulations. Methacrylate‐based random heteropolymers (RHPs), assembled via transient noncovalent linkages in water, have shown promise in an assortment of applications that harness their bio‐inspired properties. While their molecular behavior has been broadly characterized in aqueous environments, many newer applications include the use of organic solvent rather than bio‐mimetic conditions. The polymer assemblies, typically driven by the hydrophobic effect in water, are less well understood in nonaqueous solution. Here, a specific RHP system is examined which forms compact globular morphologies in highly polar or highly nonpolar environments while adopting extended conformations in solvents of intermediate polarity. The pivotal role of electrostatic interactions between charge groups in low dielectric mediums is also observed. Finally, high temperature anneal cycles are compared to room temperature transformations to illuminate barriers to remodeling upon environmental changes. [ABSTRACT FROM AUTHOR]

The flagellar filament is a helical propeller for bacterial locomotion. In external flagellates, the filaments are mostly homopolymers of a single flagellin protein. By contrast, the flagellar filaments of spirochetes are mostly heteropolymers of multiple flagellin proteins. This report seeks to investigate the role of multiple flagellin proteins using the oral spirochete Treponema denticola as a model. First, biochemical and genetic studies uncover that the flagellar filaments of T. denticola mainly comprise four proteins, FlaA, FlaB1, FlaB2, and FlaB3, in a defined stoichiometry. Second, transcriptional analyses reveal that the genes encoding these four proteins are regulated by two different transcriptional factors, sigma28 and sigma70. Third, loss‐of‐function studies demonstrate that each individual flagellin protein contributes to spirochete motility, but none of them is absolutely required. Last, we provide genetic and structural evidence that FlaA forms a "seam"‐like structure around the core and that deletion of individual flagellin protein alters the flagellar homeostasis. Collectively, these results demonstrate that T. denticola has evolved a unique mechanism to finely regulate its flagellar filament gene expression and assembly which renders the organelle with the right number, shape, strength, and structure for its distinct motility. [ABSTRACT FROM AUTHOR]

Proteins are the workhorse of life. They are the building infrastructure of living systems; they are the most efficient molecular machines known, and their enzymatic activity is still unmatched in versatility by any artificial system. Perhaps proteins’ most remarkable feature is their modularity. The large amount of information required to specify each protein’s function is analogically encoded with an alphabet of just ∼20 letters. The protein folding problem is how to encode all such information in a sequence of 20 letters. In this review, we go through the last 30 years of research to summarize the state of the art and highlight some applications related to fundamental problems of protein evolution. [ABSTRACT FROM AUTHOR]

Powered by electricity from renewable energies, electrochemical reduction of CO2 could not only efficiently alleviate the excess emission of CO2, but also produce many kinds of valuable chemical feedstocks. Among various catalysts, single atom catalysts (SACs) have attracted much attention due to their high atom utilization efficiency and expressive catalytic performances. Additionally, SACs serve as an ideal platform for the investigation of complex reaction pathways and mechanisms thanks to their explicit active sites. In this review, the possible reaction pathways for the generation of various products (mainly C1 products for SACs) were firstly summarized. Then, recent progress of SACs for electrochemical reduction of CO2 was discussed in aspect of different central metal sites. As the most popular and efficient coordination modulation strategy, introducing heteroatom was then reviewed. Moreover, as an extension of SACs, the development of dual atom catalysts was also briefly discussed. At last, some issues and challenges regarding the SACs for CO2 reduction reaction (CO2RR) were listed, followed by corresponding suggestions. [ABSTRACT FROM AUTHOR]

The molecular connectivity indices were used to investigate the effect of the spacer group structure on the value of the minimum inhibitory concentration of bis-quaternary ammonium bromide salts. QSAR model obtained allows to examine the influence of branching, multiple bonds, and heteroatoms of the spacer group on minimum inhibitory concentration value. The effect of spacer’s branches and heteroatoms on the anti–Escherichia coli activity of cationic gemini surfactants was also investigated using the atomic charges. This study leads to some significant conclusions regarding the effect of the spacer group structure on the antibacterial activity of cationic gemini surfactants against Escherichia coli. The general conclusion is that a small modification of the straight spacer chain structure can give gemini surfactant with excellent activity against such resistant bacterium as Escherichia coli. [ABSTRACT FROM AUTHOR]

A green and economically viable route without any additional activation agents and templates has been developed to synthesize biomass-derived nanoporous carbon for superior electric double-layer capacitors via direct pyrolysis of dried black liquor powders, which is the main waste in pulping and paper-making industry. The resulting carbon materials present hierarchical porosity and moderate specific surface area of 1134 m 2 g − 1 {\text{m}^{2}}\hspace{0.1667em}{\text{g}^{-1}} , as well as multi-heteroatoms co-doping such as N, S, Na and K, which exist originally in black liquor. When evaluated as electrode materials for supercapacitors in 6 M KOH aqueous electrolyte, the-prepared carbon samples deliver a significantly high gravimetric capacitance of 331 F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5 A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} in a three-electrode system. Moreover, the fabricated symmetric supercapacitor also possesses a gravimetric capacitance of 211 F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5 A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} , with an impressive long-term cycling stability of 92 % capacitance retention after 3000 cycles. This work explores a suitable and scalable approach for mass production of high-performance electrode materials with industrial wastes on the base of cost-efficiency and environment-friendship. [ABSTRACT FROM AUTHOR]

Lattice model of macromolecules adsorption has been applied to describe the separation of single-stranded DNA on a reversed phase in a water–acetonitrile mixture under isocratic and gradient modes. It has been shown that this model, extended with correlation relationships between the effective unit energy and the solvent composition, can accurately describe the features of chromatographic separation of homo- as well as heteropolynucleotides. The correlation between the calculated and experimental data has been less accurate in the case of the heteropolymers in comparison with homopolymers, due to low contribution of the entropy term of the adsorption interaction with variation of the sequence. The approaches to the model adjustment to account for the neighbor units effect have been discussed. [ABSTRACT FROM AUTHOR]

K‐ion batteries (KIBs) have attracted tremendous attention and seen significant development because of their low price, high operating voltage, and properties similar to those of Li‐ion batteries. In the field of development of full batteries, exploring high‐performing and low‐cost anode materials for K‐ion storage is a crucial challenge. Owing to their excellent cost effectiveness, abundant precursors, and environmental benignancy, hard carbons (HCs) are considered promising anode materials for KIBs. As a result, researchers have devoted much effort to quantify the properties and to understand the underlying mechanisms of HC‐based anodes. In this review, we mainly introduce the electrochemical reaction mechanism of HCs in KIBs, and summarize approaches to further improve the electrochemical performance in HC‐based materials for K‐ion storage. In addition, we also highlight some advanced in situ characterization methods for understanding the evolutionary process underlying the potassiation–depotassiation process, which is essential for the directional electrochemical performance optimization of KIBs. Finally, we raise some challenges in developing smart‐structured HC anode materials for KIBs, and propose rational design principles and perspectives serving as the guidance for the targeted optimization of HC‐based KIBs. [ABSTRACT FROM AUTHOR]

The Shanxi Formation (Shan 1 and Shan 2 Members) shales show good prospects in shale gas development in the Yan'an area of Ordos Basin. Based on the simulation experiment of hydrocarbon generation of low maturity shale samples, the hydrocarbon generation characteristics of shale samples was studied systematically. Then, combined with the geochemical analysis of shale and gas generation simulation, shale gas potential was evaluated. The results reveal that Shan 1 and Shan 2 shale samples are favorable for shale gas enrichment by and large, with C1eC5 maximum yields of 146.96e160.83 mg/g TOC and 148.48e148.67 mg/g TOC respectively at a heat rate of 20 °C/h and 2 °C/h. The Shan 1 and Shan 2 shales are basically the same in terms of organic carbon production potential of each unit. The carbon isotopic composition of alkane gas reveals that heteroatomic compounds (NSOs) cracking is an important mechanism for shale gas generation of Shanxi Formation shales, and conducive to gas generation at highto over-mature stages. Given thermal history and kinetic parameters of hydrocarbon generation, the shales of Shanxi Formation reached the maximum gas production potential in the Late Cretaceous, with a maximum yield of 160.3 mg/g TOC under present geological conditions. During geological history, the Shanxi Formation shales went through high-to over-maturity evolution, mainly producing dry gas, and their gas generation capacity was controlled by the organic matter abundance and cracking capacity. The gas generation potential of Shan 2 shale is higher than that of Shan 1, due to its higher TOC. [ABSTRACT FROM AUTHOR]

Most of the presently known thermosensitive shape‐memory polymers suitable for 4D printing have insufficient mechanical strength and thermal stability that restricts their potential areas of application. Here, new photosensitive compositions (PSCs) based on aromatic heterochain polymers – poly‐N,N′‐(m‐phenylene)isophthalamide (MPA) or poly‐2,2′‐(p‐oxydiphenylene)‐5,5′‐dibenzimidazole (OPBI) – for DLP printing are proposed. Thermal post‐curing and supercritical carbon dioxide (scCO2) are used for post‐processing of the structures. During the scCO2 treatment the removal of unreacted monomeric component (N,N‐dimethylacrylamide) and its uncrosslinked oligomers is accompanied by the preservation of the initial degree of crosslinking. The more stable shrinkage is observed for the combined post‐processing method (T°+scCO2) in the case of OPBI‐PSC and after the heat treatment for MPA‐PSC specimens. The method of post‐processing and the nature of the heterochain polymer strongly affect the mechanical properties and thermal resistance of the structures. The tensile strength has the maximum value after the thermal post‐treatment (101.1 ± 7.1 and 78.4 ± 5.1 MPa of OPBI‐PSC and MPA‐PSC, respectively). The intense destruction of the materials is observed at 393 and 408 °C for MPA‐PSC and OPBI‐PSC, respectively. Moreover, the 4D‐printed structures exhibit excellent shape memory performance at transition temperatures >100 °C, thus have a great potential for the use in aerospace, robotics, sensorics. [ABSTRACT FROM AUTHOR]

Modification of polycaproamide by 1H,1H,13H-trihydroperfluorotridecan-1-ol immobilized on montmorillonite produced an F-containing polymer composite. The structure of the resulting composite was investigated using x-ray structure analysis and solid-state 19F NMR spectroscopy. The polymorphous composition of this heterochain polymer was shown to reorganize to enhance its thermal stability and diminish its flammability. Possible mechanisms for the stabilizing effect of the used modifier that were related to the involvement of organo-clay paramagnetic centers in the binding of macroradicals formed during thermal decomposition of macromolecular chains were discussed. [ABSTRACT FROM AUTHOR]

Molybdenum carbide (MoxC) with variable phase structure possesses flexible hydrogen‐binding energy (HBE), which is a promising hydrogen evolution reaction (HER) catalyst. Herein, a hybrid multiphase MoxC freestanding film coupled with Co3Mo (CM/MoxC@NC) is synthesized through the electrospinning method supplemented by the heteroatom incorporation. CM/MoxC@NC surpasses its pure phase counterparts and exhibits remarkable catalytic activity at 114 mV to deliver a current density of 10 mA cm−2 in acid, which is among the first‐rate level performance reported for MoxC‐based catalysts. The subsequent ex situ and in situ characterizations reveal a phase transition mechanism based on self‐catalysis that CoOx depletes the coordinated C of α‐MoC via the interaction, which realizes the assembly of weak HBE α‐MoC and strong HBE β‐Mo2C, and the enhanced utilization of active materials as well. The multiple structures with optimal HBE are in favor of the stepwise reactions of HER, as the study of the correlation between HBE and phase structure revealed. This study discloses the underlying phase transition mechanism and highlights the HBE–structure relationship that should be considered for catalyst design. [ABSTRACT FROM AUTHOR]

Human cytoplasmic ferritins are heteropolymers of H and L subunits containing a catalytic ferroxidase center and a nucleation site for iron biomineralization, respectively. Here, ESI-MS successfully detected labile metal–protein interactions revealing the formation of tetra- and octa-iron clusters bound to L subunits, as previously underscored by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Density functional theory calculations were carried out to investigate the evolvement of charge transport properties of a set of new discotic systems as a function of ring and heteroatom (B, Si, S, and Se) substitution on the basic structure of perylene. The replacement of six-membered rings by five-membered rings in the reference compound has shown a prominent effect on the electron reorganization energy that decreases ∼0.2 eV from perylene to the new carbon five-membered ring derivative. Heteroatom substitution with boron also revealed to lower the LUMO energy level and increase the electron affinity, therefore lowering the electron injection barrier compared to perylene. Since the rate of the charge transfer between two molecules in columnar discotic systems is strongly dependent on the orientation of the stacked cores, the total energy and transfer integral of a dimer as a disc is rotated with respect to the other along the stacking axis have been predicted. Aimed at obtaining a more realistic approach to the bulk structure, the molecular geometry of clusters made up of five discs was fully optimized, and charge transfer rate and mobilities were estimated for charge transport along a one dimensional pathway. Heteroatom substitution with selenium yields electron transfer integral values ∼0.3 eV with a relative disc orientation of 25°, which is the preferred angle according to the dimer energy profile. All the results indicate that the tetraselenium-substituted derivative, not synthetized so far, could be a promising candidate among those studied in this work for the fabrication of n-type semiconductors based on columnar discotic liquid crystals materials. [ABSTRACT FROM AUTHOR]

Shale gas fracturing flowback fluid contains various degradation difficulty organic compounds after hydraulic fracturing. A hybrid treatment method was developed for treating flowback and produced water (FPW) using pre-treatment (NaClO) followed by the expanded granular sludge bed (EGSB) and moving bed biofilm reactor (MBBR). Gas chromatography–mass spectrometry (GC-MS) was employed to detect organic composition in the FPW, the pre-treated FPW, EGSB and MBBR effluent. FPW had high chemical oxygen demand (COD) (3278 mg/L) and the majority of organic compounds in the FPW composed of alkanes and heteroatomic compounds with polymers and polarity. 20% COD removal was achieved after adding 5 g/L of NaClO in FPW (pH = 7, stirring for 20 mins) as pre-treatment and > C30 alkanes in FPW were decomposed a lot in the pre-treatment process. The pre-treated FPW was diluted (volumetric ratio of 20%/50%) with synthetic wastewater/pure water. In the final stage of operation, Cl− and COD concentration of influent to EGSB-MBBR system was around 7000 ± 100 mg/L and 3000 mg/L. EGSB-MBBR system achieved 93.84% COD removal rate, in which EGSB dominated COD removal (>80%). According to the GC-MS results, EGSB had an increase of C11-C30 compounds and a decrease of less C1-C10 content due to the consumption of > C30 compounds and low molecular weight (LWM) compounds. Meanwhile, aerobic microorganisms in MBBR metabolized LWM organics which contributed a lot to the COD removal (25.06∼68. 22%). The results indicated that the pre-treatment and biological EGSB-MBBR system could be an efficient option used for FPW treating. [ABSTRACT FROM AUTHOR]

A general formalism to compute configurational properties of proteins and other heteropolymers with an arbitrary sequence of charges and non-uniform excluded volume interaction is presented. A variational approach is utilized to predict average distance between any two monomers in the chain. The presented analytical model, for the first time, explicitly incorporates the role of sequence charge distribution to determine relative sizes between two sequences that vary not only in total charge composition but also in charge decoration (even when charge composition is fixed). Furthermore, the formalism is general enough to allow variation in excluded volume interactions between two monomers. Model predictions are benchmarked against the all-atom Monte Carlo studies of Das and Pappu [Proc. Natl. Acad. Sci. U. S. A. 110, 13392 (2013)] for 30 different synthetic sequences of polyampholytes. These sequences possess an equal number of glutamic acid (E) and lysine (K) residues but differ in the patterning within the sequence. Without any fit parameter, the model captures the strong sequence dependence of the simulated values of the radius of gyration with a correlation coefficient of R² = 0.9. The model is then applied to real proteins to compare the unfolded state dimensions of 540 orthologous pairs of thermophilic and mesophilic proteins. The excluded volume parameters are assumed similar under denatured conditions, and only electrostatic effects encoded in the sequence are accounted for. With these assumptions, thermophilic proteins are found--with high statistical significance--to have more compact disordered ensemble compared to their mesophilic counterparts. The method presented here, due to its analytical nature, is capable of making such high throughput analysis of multiple proteins and will have broad applications in proteomic studies as well as in other heteropolymeric systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • GLDHs was easily synthesized with low-cost materials via simple co-precipitation. • Intercalating way of GAa in GLDHs was proposed via anion sizes analysis. • GLDHs3 carbonized well under high temperature, but 180 °C showed little impact. • GLDHs possessed high filling property and performed good flame retardancy in EP. • GLDHs2 kept 88% tensile strength of EP composites with a high filling of 40 wt.%. Epoxy resin (EP) is a polymer that is widely used in different aspects of life, but its flammability property limits its fields of applications. Most flame retardants at present cannot be applied practically in scale due to their toxicity, incompatibility in polymers, degraded mechanical property or high cost of raw materials and comprehensive preparation process. Layered double hydroxides intercalated by gluconic acid anion (GLDHs) may serve as a new approach. GLDHs with Mg/Al ratio of 3/1 and 2/1 were first coprecipitated with low-cost green reactants, MgCl 2 ·6H 2 O, AlCl 3 ·6H 2 O, NaOH and sodium gluconate. Their structures were confirmed by X-ray diffractions (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and elemental analysis; their thermal properties were analyzed by thermo gravimetric analysis (TGA). Composites containing 40 wt.% GLDHs were easily manufactured with normal magnetic stirring without any filler precipitation. The combustion properties of the composites filled with 40 wt.% GLDHs2 are as follows: the limit oxygen index (LOI) could rise to 29.8% from 25.2% of pristine EP; UL-94 can reach V-1 level with total burning time of only 12.1 s without dropping; compared to pristine EP, the heat release rate peak (PHRR) could drop to 30% with heavy decrease in the smoke production rate and CO production rate. Dynamic mechanical thermal analysis (DMA) tests showed that the addition of 40 wt.% GLDHs had little impact on the glass transition temperature of the composites and could slightly improve their rigidity and toughness. Tensile strength of the composites filled with 40 wt.% GLDHs2 was almost close to 88% of the tensile strength of pristine EP. Above all, GLDHs with good compatibility in polymers can serve as a promising environmental friendly and low-cost flame retardant for EP and other heterochain polymers. [ABSTRACT FROM AUTHOR]

It is widely hypothesized that removing cellular transfer RNAs (tRNAs)—making their cognate codons unreadable—might create a genetic firewall to viral infection and enable sense codon reassignment. However, it has been impossible to test these hypotheses. In this work, following synonymous codon compression and laboratory evolution in Escherichia coli, we deleted the tRNAs and release factor 1, which normally decode two sense codons and a stop codon; the resulting cells could not read the canonical genetic code and were completely resistant to a cocktail of viruses. We reassigned these codons to enable the efficient synthesis of proteins containing three distinct noncanonical amino acids. Notably, we demonstrate the facile reprogramming of our cells for the encoded translation of diverse noncanonical heteropolymers and macrocycles. [ABSTRACT FROM AUTHOR]

Metal--organic frameworks (MOFs) are crystalline materials with permanent porosity, composed of metal nodes and organic linkers whose well-ordered arrangement enables them to act as ideal templates to produce materials with a uniform distribution of heteroatom and metal elements. The hybrid nature of MOFs, well-defined pore structure, large surface area and tunable chemical composition of their precursors, led to the preparation of various MOF-derived porous carbons with controlled structures and compositions bearing some of the unique structural properties of the parent networks. In this regard, an important class of MOFs constructed with porphyrin ligands were described, playing significant roles in the metal distribution within the porous carbon material. The most striking early achievements using porphyrin-based MOF porous carbons are here summarized, including preparation methods and their transformation into materials for electrochemical reactions. [ABSTRACT FROM AUTHOR]

Cell assembly and synthesis of calcined polyphosphazene modified NiCo 2 O 4 (NiCo 2 O 4 @PZSC) and phosphated petroleum coke (p-PC). [Display omitted] • P-doped porous carbon (p-PC) was designed as the negative electrode. • Heteroatomic polymer carbon modified NiCo 2 O 4 (NiCo 2 O 4 @PZSC) was designed as the positive electrode. • The p-PC (−) exhibits excellent cycling stability (99 %, 10,000r) with specific capacitance of 197.5 F g−1. • The assembled NiCo 2 O 4 @PZSC (+)//p-PC (−) shows high energy and power density (30.5 Wh kg−1, 800 W kg−1). The inexpensive assembly of high-performance supercapacitors has always been a research hotspot in energy storage. Herein, we used simple procedures and inexpensive raw materials to assemble a high-performance supercapacitor with p-doped porous carbon (p-PC) as the negative electrode and heteroatomic polymer carbon modified NiCo 2 O 4 (NiCo 2 O 4 @PZSC) as the positive electrode. The p-PC with excellent electrochemical properties (197.5 F g−1, 99 % after 10,000r) was prepared by chemical modification using cheap petroleum coke as raw material. The NiCo 2 O 4 @PZSC was obtained by in-situ coating polyphosphazene on NiCo 2 O 4 nanowires and calcination in air, exhibiting an admirable specific capacitance of 841 F g−1 with suitable cyclic stability (81 %, 8000r). The assembled hybrid supercapacitor NiCo 2 O 4 @PZSC (+)//p-PC (−) embodies high energy, power density and cyclic stability (30.5 Wh kg−1, 800 W kg−1, 90 %, 10,000r). This work opens up a new path to rationally design heteroatom-doped carbon modified binary transition metals for efficient supercapacitors. [ABSTRACT FROM AUTHOR]

Polymerizing and filament‐forming proteins are instrumental for numerous cellular processes such as cell division and growth. Their function in stabilization and localization of protein complexes and replicons is achieved by a filamentous structure. Known filamentous proteins assemble into homopolymers consisting of single subunits – for example, MreB and FtsZ in bacteria – or heteropolymers that are composed of two subunits, for example, keratin and α/β tubulin in eukaryotes. Here, we describe two novel coiled‐coil‐rich proteins (CCRPs) in the filament‐forming cyanobacterium Anabaena sp. PCC 7120 (hereafter Anabaena) that assemble into a heteropolymer and function in the maintenance of the Anabaena multicellular shape (termed trichome). The two CCRPs – Alr4504 and Alr4505 (named ZicK and ZacK) – are strictly interdependent for the assembly of protein filaments in vivo and polymerize nucleotide independently in vitro, similar to known intermediate filament (IF) proteins. A ΔzicKΔzacK double mutant is characterized by a zigzagged cell arrangement and hence a loss of the typical linear Anabaena trichome shape. ZicK and ZacK interact with themselves, with each other, with the elongasome protein MreB, the septal junction protein SepJ and the divisome associate septal protein SepI. Our results suggest that ZicK and ZacK function in cooperation with SepJ and MreB to stabilize the Anabaena trichome and are likely essential for the manifestation of the multicellular shape in Anabaena. Our study reveals the presence of filament‐forming IF‐like proteins whose function is achieved through the formation of heteropolymers in cyanobacteria. [ABSTRACT FROM AUTHOR]

The rapid development of science and technology has brought urgent demand for diversity in polymer structures and functionalities, and the pursuit of new polymerizations and new polymer structures is the constant goal in polymer chemistry. Multicomponent polymerizations and multicomponent reaction involving polymer synthesis have been demonstrated to be a very powerful tool for the construction of functional polymers with diversified structures and advanced functionalities, which have become a prosperous branch of polymer chemistry. Calvo, Wagener, Sumerlin, and co-workers have prepared hyperbranched aminobisphosphonic acid polymers via reversible addition-fragmentation chain transfer self-condensing vinyl polymerization of an acrylamide-functional chain transfer monomer, followed by the introduction of the aminobisphosphonate functional group through a three-component Kabachnick-Fields reaction (2000578). [Extracted from the article]

Heterochain polymers such as DNA and proteins are abundant in nature, but they are not ubiquitous in man‐made polymers due to the synthetic difficulties. Traditional polymerization methodologies including chain polymerization, step‐growth polymerization, and coordination polymerization all show obvious drawbacks in synthesizing heterochain polymers. The alkyne multicomponent polymerizations (MCPs) developed in the early 2000s open a new door for the synthesis of conjugated heterochain polymers with diverse structures and unique properties. This review presents the progress in novel heterochain polymers constructed by alkyne‐based MCPs in the last three years. The unique properties and high‐tech applications brought by heteroatoms and MCPs are summarized and perspectives on future directions are also discussed. [ABSTRACT FROM AUTHOR]

Acenes and azaacenes lie at the core of molecular materials' applications due to their important optical and electronic features. A critical aspect is provided by their heteroatom multiplicity, which can strongly affect their properties. Here we report pyrazinacenes containing the dihydro-decaazapentacene and dihydro-octaazatetracene chromophores and compare their properties/functions as a model case at an oxidizing metal substrate. We find a distinguished, oxidation-state-dependent conformational adaptation and self-assembly behaviour and discuss the analogies and differences of planar benzo-substituted decaazapentacene and octaazatetracene forms. Our broad experimental and theoretical study reveals that decaazapentacene is stable against oxidation but unstable against reduction, which is in contrast to pentacene, its C–H only analogue. Decaazapentacenes studied here combine a planar molecular backbone with conformationally flexible substituents. They provide a rich model case to understand the properties of a redox-switchable π-electronic system in solution and at interfaces. Pyrazinacenes represent an unusual class of redox-active chromophores. Acenes are a promising class of organic materials with distinctive electronic and optical properties. Here decaazapentacene and octaazatetracenes are prepared and their self-assembly behaviour at different oxidation states is analysed. [ABSTRACT FROM AUTHOR]

We study the parameter sensitivity of hetero-polymeric DNA within the purview of DNA breathing dynamics. The degree of correlation between the mean bubble size and the model parameters is estimated for this purpose for three different DNA sequences. The analysis leads us to a better understanding of the sequence dependent nature of the breathing dynamics of hetero-polymeric DNA. Out of the 14 model parameters for DNA stability in the statistical Poland-Scheraga approach, the hydrogen bond interaction ∈hb(AT) for an AT base pair and the ring factor ξ turn out to be the most sensitive parameters. In addition, the stacking interaction ∈st (TA-TA) for an TA-TA nearest neighbor pair of base-pairs is found to be the most sensitive one among all stacking interactions. Moreover, we also establish that the nature of stacking interaction has a deciding effect on the DNA breathing dynamics, not the number of times a particular stacking interaction appears in a sequence. We show that the sensitivity analysis can be used as an effective measure to guide a stochastic optimization technique to find the kinetic rate constants related to the dynamics as opposed to the case where the rate constants are measured using the conventional unbiased way of optimization. [ABSTRACT FROM AUTHOR]