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Widespread use of plant protection agents in agriculture is a major cause of pollution. Apart from active ingredients, the environmental impact of auxiliary synthetic polymers should be minimized if they are highly persistent. An alternative to synthetic polymers is the use of natural polysaccharides, which are abundant and biodegradable. In this study, we explore pectin microgels functionalized with anchor peptides (P‐MAPs) to be used as an alternative biobased pesticide delivery system. Using copper as the active ingredient, P‐MAPs effectively prevented infection of grapevine plants with downy mildew under semi‐field conditions on par with commercial copper pesticides. By using anchor peptides, the microgels tightly bind to the leaf surface, exhibiting excellent rain fastness and prolonged fungicidal activity. Finally, P‐MAPs are shown to be easily degradable by enzymes found in nature, demonstrating their negligible long‐term impact on the environment. [ABSTRACT FROM AUTHOR]

Material-binding peptides (MBPs) have emerged as a diverse and innovation-enabling class of peptides in applications such as plant-/human health, immobilization of catalysts, bioactive coatings, accelerated polymer degradation and analytics for micro-/nanoplastics quantification. Progress has been fuelled by recent advancements in protein engineering methodologies and advances in computational and analytical methodologies, which allow the design of, for instance, material-specific MBPs with fine-tuned binding strength for numerous demands in material science applications. A genetic or chemical conjugation of second (biological, chemical or physical property-changing) functionality to MBPs empowers the design of advanced (hybrid) materials, bioactive coatings and analytical tools. In this review, we provide a comprehensive overview comprising naturally occurring MBPs and their function in nature, binding properties of short man-made MBPs (<20 amino acids) mainly obtained from phage-display libraries, and medium-sized binding peptides (20–100 amino acids) that have been reported to bind to metals, polymers or other industrially produced materials. The goal of this review is to provide an in-depth understanding of molecular interactions between materials and material-specific binding peptides, and thereby empower the use of MBPs in material science applications. Protein engineering methodologies and selected examples to tailor MBPs toward applications in agriculture with a focus on plant health, biocatalysis, medicine and environmental monitoring serve as examples of the transformative power of MBPs for various industrial applications. An emphasis will be given to MBPs' role in detecting and quantifying microplastics in high throughput, distinguishing microplastics from other environmental particles, and thereby assisting to close an analytical gap in food safety and monitoring of environmental plastic pollution. In essence, this review aims to provide an overview among researchers from diverse disciplines in respect to material-(specific) binding of MBPs, protein engineering methodologies to tailor their properties to application demands, re-engineering for material science applications using MBPs, and thereby inspire researchers to employ MBPs in their research. [ABSTRACT FROM AUTHOR]

Alcohol dehydrogenases (ADHs) are synthetically important biocatalysts for the asymmetric synthesis of chiral alcohols. The catalytic performance of ADHs in the presence of organic solvents is often important since most prochiral ketones are highly hydrophobic. Here, the organic solvent tolerance of KpADH from Kluyveromyces polyspora was semi‐rationally evolved. Using tolerant variants obtained, meticulous experiments and computational studies were conducted to explore properties including stability, activity and kinetics in the presence of various organic solvents. Compared with WT, variant V231D exhibited 1.9‐fold improvement in ethanol tolerance, while S237G showed a 6‐fold increase in catalytic efficiency, a higher T5015$$ {\mathrm{T}}_{50}^{15} $$, as well as 15% higher tolerance in 7.5% (v/v) ethanol. Based on 3 × 100 ns MD simulations, the increased tolerance of V231D and S237G against ethanol may be ascribed to their enhanced ability in retaining water molecules and repelling ethanol molecules. Moreover, 6.3‐fold decreased KM value of V231D toward hydrophilic ketone substrate confirmed its capability of retaining hydration shell. Our results suggest that retaining hydration shell surrounding KpADH is critical for its tolerance to organic solvents, as well as catalytic performance. This study provides useful guidance for engineering organic solvent tolerance of KpADH and other ADHs. [ABSTRACT FROM AUTHOR]

A typical component of polymer waste is polystyrene (PS) used in numerous applications, but degraded only slowly in the environment due to its hydrophobic properties. To increase the reactivity of polystyrene, polar groups need to be introduced. Here, biohybrid catalysts based on the engineered anchor peptide LCI_F16C are presented, which are capable of attaching to polystyrene microparticles and hydroxylating benzylic C−H bonds in polystyrene microparticles using commercially available oxone as oxidant. LCI peptides achieve a dense surface coverage of PS through monolayer formation within minutes in aqueous solutions at ambient temperature. The catalytically active cobalt cofactor Co‐L1 or Co‐L2 with a modified NNNN macrocyclic TACD ligand (TACD=1,4,7,10‐tetraazacyclododecane) is covalently bound to the anchor peptide LCI through a maleimide linker. Compared to the free cofactors, a 12‐ to 15‐fold improvement in catalytic activity using biohybrid catalysts based on LCI_F16C was observed. [ABSTRACT FROM AUTHOR]

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Sortase‐mediated ligation (SML) has emerged as a powerful and versatile methodology for site‐specific protein conjugation, functionalization/labeling, immobilization, and design of biohybrid molecules and systems. However, the broader application of SML faces several challenges, such as limited activity and stability, dependence on calcium ions, and reversible reactions caused by nucleophilic side‐products. Over the past decade, protein engineering campaigns and particularly directed evolution, have been extensively employed to overcome sortase limitations, thereby expanding the potential application of SML in multiple directions, including therapeutics, biorthogonal chemistry, biomaterials, and biosensors. This review provides an overview of achieved advancements in sortase engineering and highlights recent progress in utilizing SML in combination with other state‐of‐the‐art chemical and biological methodologies. The aim is to encourage scientists to employ sortases in their conjugation experiments. [ABSTRACT FROM AUTHOR]

The development of efficient and environmentally friendly plant protection systems is one of the major challenges for a sustainable agriculture of the future. Citrus canker caused by the pathogen Xanthomonas citri subsp. citri (X. citri) affects all cultivated citrus species worldwide and is responsible for enormous economic losses and restrictions in international trade. Currently used commercial copper‐based formulations are the origin of contamination for soil and groundwater, affecting local ecosystems and human health. A copper‐free sustainable microgel‐based plant protection system able to efficiently combat X. citri is developed. Microgels decorated with anchor peptides exhibit strong non‐covalent attachment to the surface of orange leaves and have the ability to release hexyl gallate, which inhibits the growth and spreading of pathogens. The tailored design of the microgel network allows high loadings of hexyl gallate (up to 40 wt.%) and a controlled release of gallates from microgels that provide long‐term protection. The antibacterial activity of the hexyl gallate‐loaded microgels is demonstrated by various in vitro assays as well as on orange plants in greenhouse settings. The experimental results suggest that the developed sustainable microgel‐based plant protection system for citrus trees allows efficient abatement of X. citri and reduces environmental pollution caused by copper formulations. [ABSTRACT FROM AUTHOR]

Artificial metalloenzymes have emerged as biohybrid catalysts that allow to combine the reactivity of a metal catalyst with the flexibility of protein scaffolds. This work reports the artificial metalloenzymes based on the β‐barrel protein nitrobindin NB4, in which a cofactor [CoIIX(Me3TACD‐Mal)]+X− (X=Cl, Br; Me3TACD=N,N',N''‐trimethyl‐1,4,7,10‐tetraazacyclododecane, Mal=CH2CH2CH2NC4H2O2) was covalently anchored via a Michael addition reaction. These biohybrid catalysts showed higher efficiency than the free cobalt complexes for the oxidation of benzylic C(sp3)−H bonds in aqueous media. Using commercially available oxone (2KHSO5 ⋅ KHSO4 ⋅ K2SO4) as oxidant, a total turnover number of up to 220 and 97 % ketone selectivity were achieved for tetralin. As catalytically active intermediate, a mononuclear terminal cobalt(IV)‐oxo species [Co(IV)=O]2+ was generated by reacting the cobalt(II) cofactor with oxone in aqueous solution and characterized by ESI‐TOF MS. [ABSTRACT FROM AUTHOR]