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Controlled protein assembly and crystallization is necessary as a means of generating diffraction‐quality crystals as well as providing a basis for new types of biomaterials. Water‐soluble calixarenes are useful mediators of protein crystallization. Recently, it was demonstrated that Ralstonia solanacearum lectin (RSL) co‐crystallizes with anionic sulfonato‐calix[8]arene (sclx8) in three space groups. Two of these co‐crystals only grow at pH ≤ 4 where the protein is cationic, and the crystal packing is dominated by the calixarene. This paper describes a fourth RSL–sclx8 co‐crystal, which was discovered while working with a cation‐enriched mutant. Crystal form IV grows at high ionic strength in the pH range 5–6. While possessing some features in common with the previous forms, the new structure reveals alternative calixarene binding modes. The occurrence of C2‐symmetric assemblies, with the calixarene at special positions, appears to be an important result for framework fabrication. Questions arise regarding crystal screening and exhaustive searching for polymorphs. [ABSTRACT FROM AUTHOR]

Protein frameworks are an emerging class of biomaterial with medical and technological applications. Frameworks are studied mainly by X-ray diffraction or scattering techniques. Complementary strategies are required. Here, we report solid-state NMR analyses of a microcrystalline protein–macrocycle framework and the rehydrated freeze-dried protein. This methodology may aid the characterization of low-crystallinity frameworks. [ABSTRACT FROM AUTHOR]

We have identified a novel shell protein, accripin11, as a major soluble component of the calcitic prisms of the fan mussel Pinna nobilis. Initially retrieved from a cDNA library, its full sequence is confirmed here by transcriptomic and proteomic approaches. The sequence of the mature protein is 103 residues with a theoretical molecular weight of 11 kDa and is moderately acidic (pI 6.74) except for its C‐terminus which is highly enriched in aspartic acid. The protein exhibits a peculiar cysteine pattern in its central domain. The full sequence shares similarity with six other uncharacterized molluscan shell proteins from the orders Ostreida, Pteriida and Mytilida, all of which are pteriomorphids and produce a phylogenetically restricted pattern of nacro‐prismatic shell microstructures. This suggests that accripin11 is a member of a family of clade‐specific shell proteins. A 3D model of accripin11 was predicted with AlphaFold2, indicating that it possesses three short alpha helices and a disordered C‐terminus. Recombinant accripin11 was tested in vitro for its ability to influence the crystallization of CaCO3, while a polyclonal antibody was able to locate accripin11 to prismatic extracts, particularly in the acetic acid‐soluble matrix. The putative functions of accripin11 are further discussed in relation to shell biomineralization. [ABSTRACT FROM AUTHOR]

Owing to their remarkable features, calix[n]arenes are being exploited to study different aspects of molecular recognition, including protein complexation. Different complexation modes have been described, depending on the moieties that complement the aromatic cavity, allowing for function regulation and/or controlled assembly of the protein target. Here, a rigid cone calix[4]arene, bearing four anionic alanine units at the upper rim, was tested as a ligand for cytochrome c. Cocrystallization attempts were unfruitful, preventing a solid-state study of the system. Next, the complex was studied using NMR spectroscopy, which revealed the presence of two binding sites at lysine residues with dissociation constants (Kd) in the millimolar range. [ABSTRACT FROM AUTHOR]

Research has been conducted on plastocyanin-cytochrome f interactions. The study of Tyr12 and Pro14 residues' contributions to these interactions has been carried out via NMR analysis of plastocyanin and cytochrome f complex, and the results demonstrate that this complex involves hydrophobic patch on plastocyanin.

We report (U-Th)/He apatite ages from the crystalline core of the Bighorn Mountains and compare the exhumation history derived from those ages with the exhumation history determined from sedimentary rocks in the adjacent Powder River and Bighorn basins. Our (U-Th)/He apatite ages range from 62 to 369 Ma and represent a pre-Laramide He partial retention zone that was deformed and uplifted at ca. 65 [+ or -] 5 Ma. The geometry of the He partial retention zone indicates that the basement in the Bighorn Mountains is deformed into a doubly plunging anticline. The preservation of a pre-Laramide partial retention zone in the upper few hundred meters of Precambrian basement indicates that in general, the temperature at the Cambrian unconformity did not exceed the apatite He closure temperature. This is difficult to reconcile with evidence from adjacent basins for thick sequences of sedimentary rocks (3-4 km) prior to 65 Ma, and normal modern geothermal gradients. Either the range was never deeply buried ( Keywords: Bighorn Mountains, helium, U/Th, geochronology, exhumation, dating.

The (NMR) is used to investigate the complex of the photosynthetic redox partners plastocyanin and cytochrome f (cytf) from the thermophilic cyanobacterium, Phormidium laminosum. It was found that the complex interface involves the hydrophobic patch of poplar (Pc) and the heme region of cytf and also the plastocyanin-cytf complex from P. laminosum was predominantly controlled by hydrophobic interactions.

One approach to protein assembly involves water‐soluble supramolecular receptors that act like glues. Bionanoarchitectures directed by these scaffolds are often system‐specific, with few studies investigating their customization. Herein, the modulation of cucurbituril‐mediated protein assemblies through the inclusion of peptide tectons is described. Three peptides of varying length and structural order were N‐terminally appended to RSL, a β‐propeller building block. Each fusion protein was incorporated into crystalline architectures mediated by cucurbit[7]uril (Q7). A trimeric coiled‐coil served as a spacer within a Q7‐directed sheet assembly of RSL, giving rise to a layered material of varying porosity. Within the spacer layers, the coiled‐coils were dynamic. This result prompted consideration of intrinsically disordered peptides (IDPs) as modulatory tectons. Similar to the coiled‐coil, a mussel adhesion peptide (Mefp) also acted as a spacer between protein–Q7 sheets. In contrast, the fusion of a nucleoporin peptide (Nup) to RSL did not recapitulate the sheet assembly. Instead, a Q7‐directed cage was adopted, within which disordered Nup peptides were partially "captured" by Q7 receptors. IDP capture occurred by macrocycle recognition of an intrapeptide Phe‐Gly motif in which the benzyl group was encapsulated by Q7. The modularity of these protein–cucurbituril architectures adds a new dimension to macrocycle‐mediated protein assembly. Segregated protein crystals, with alternating layers of high and low porosity, could provide a basis for new types of materials. [ABSTRACT FROM AUTHOR]

Water soluble calixarenes are versatile mediators of protein assembly, including the fabrication of crystalline frameworks. Here, we report the X-ray crystal structure of cytochrome c (cytc) co-crystallised with two different calixarenes: phosphonato-calix[6]arene (pclx6) and sulfonato-calix[8]arene (sclx8). Each calixarene type acts as an independent molecular glue that mediates cytc dimers within the crystal. The calixarene-mediated dimers combine to yield chains of cytc-sclx8-cytc-pclx6-pclx6 repeating units. These supramolecular copolymer units pack together, via a protein-protein interface, to yield a porous dendrite-like assembly. Interestingly, the tri-component framework has features in common with previously reported structures of cytc in complex with pclx6 or sclx8. Known protein-calixarene 'building blocks' combine in novel ways to yield the tri-component assembly, highlighting the versatility of calixarene molecular glues in protein crystal engineering. [ABSTRACT FROM AUTHOR]

• Pancreatic acinar cell carcinoma (ACC) may present with pancreatic panniculitis. • Complete surgical resection of ACC can successfully treat pancreatic panniculitis. • Aggressive surgery for ACC can lead to prolonged disease-free survival. Pancreatic panniculitis is a rare manifestation of benign and malignant pancreatic disease. The presentation of pancreatic panniculitis is non-specific and thus diagnosis is often delayed. When associated with malignancy, pancreatic panniculitis confers a poor prognosis. This case demonstrates the successful surgical management of this paraneoplastic phenomenon following resection of the underlying pancreatic acinar cell carcinoma and associated liver metastasis. A 71-year-old female with debilitating subcutaneous lower limb lesions had a delayed diagnosis of pancreatic panniculitis. A formal diagnosis of pancreatic acinar cell carcinoma with liver metastasis was established and the disease was determined to be resectable. Pre-operatively, serum lipase measured 10,825 U/L. The patient proceeded to an open left hemihepatectomy and radical distal pancreatectomy with complete resection of malignant disease. Six days post-operatively the serum lipase levels normalised, and the panniculitis began to settle. The patient proceeded to adjuvant FOLFORINOX chemotherapy. Twenty months post-surgery, the patient remains disease-free and without any evidence of panniculitis. Due to the rarity of pancreatic acinar cell carcinoma, guidelines based on prospective data do not exist. Most management is based on retrospective analyses. A survival benefit may be achieved with more aggressive surgical management compared to other pancreatic cancer types. Pancreatic acinar cell carcinoma may show a slower rate of disease progression, an increased likelihood of resectability of disease at presentation and is more likely to undergo potentially curative resection. Aggressive surgical management of resectable metastatic pancreatic acinar cell carcinoma can treat pancreatic panniculitis and provide sustained disease-free survival from pancreatic cancer. [ABSTRACT FROM AUTHOR]

A crystalline biohybrid with a 4 : 1 protein : cucurbituril mass ratio is presented. This result was achieved by engineering additional cucurbit[7]uril (Q7) binding sites into a β-propeller protein. In contrast to the parent protein, Q7-controlled assembly of the engineered variant occurred in solution, as evidenced by NMR and SAXS measurements. [ABSTRACT FROM AUTHOR]

A co-crystal structure of sulfonato-calix[8]arene (sclx8) and trimethylanilinium-porphyrin (tmap) at 1.0 Å resolution is reported. The oppositely charged macrocycles formed an alternating stacked assembly. Crystal packing was completed by peripheral porphyrins that interlinked neighbouring stacks. Numerous cavities, presented by the calixarenes, were occupied by 2-methyl-2,4-pentanediol (the precipitant) resulting in an unusually high Z′. [ABSTRACT FROM AUTHOR]

The article describes a consociational power-sharing arrangement between Israel and Palestine. Topics discussed include citizenship rights of the Palestine minority in Israel and the Israeli minority in Palestine, the provision of at lease one cabinet-level position to the minorities in each government, and allowing Israeli settlers in the West Bank.

The effect of [pi]-interactions with a His ligand is examined in a family of copper-containing redox metalloproteins. The studies have shown that protonation of the His ligand is the main feature that is most affected by the introduction of a [pi]-interaction.

A study was conducted to analyze the crystal packing interfaces in three crystal forms of plastocyanin, an integral component of the photosynthetic electron transport chain and their potential relevance to in vivo supramolecular assemblies. Symmetry-related protein chains within the crystals were found to have Cu-Cu separations of

The complexes of plastocyanin and cytochrome f (Pc:Cf) from Nostoc are analyzed by heteronuclear nuclear magnetic resonance (NMR) spectroscopy. The studies of the crossed complexes show that these different interactions are due to the surface properties of the plastocyanins.

Kostiainen and co‐workers claim to have prepared crystals of ferritin by "electrostatically bridging" the protein with a cationic pillar[5]arene. Questions remain regarding the contribution of the pillar[5]arene to protein assembly and the putative role as a molecular glue. [ABSTRACT FROM AUTHOR]

Plastocyanin and cytochrome c6 function as electron shuttles between cytochrome f and photosystem I in the photosynthetic redox chain. General features and other details of the molecular interfaces found in the complexes, by the n uclear magnetic resonance studies, are revealed.

Co-crystallization of a 2 kDa tether-free sulfonated foldamer and the 13 kDa lysine-rich cytochrome c yielded a remarkable biohybrid assembly with chiral resolution of the foldamer helix handedness. In the crystal a ∼5 nm foldamer stack was surrounded by eight molecules of protein. NMR and CD experiments suggest interesting differences in the solution state recognition processes. [ABSTRACT FROM AUTHOR]

Supramolecular receptors such as water‐soluble calixarenes are in development as 'molecular glues' for protein assembly. Here, we obtained cocrystals of sulfonato‐calix[6]arene (sclx6) and yeast cytochrome c (cytc) in the presence of imidazole. A crystal structure at 2.65 Å resolution reveals major structural rearrangement and disorder in imidazole‐bound cytc. The largest protein‐calixarene interface involves 440 Å2 of the protein surface with key contacts at Arg13, Lys73, and Lys79. These lysines participate in alkaline transitions of cytc and are part of Ω‐loop D, which is substantially restructured in the complex with sclx6. The structural modification also includes Ω‐loop C, which is disordered (residues 41–55 inclusive). These results suggest the possibility of using supramolecular scaffolds to trap partially disordered proteins. [ABSTRACT FROM AUTHOR]

Controlled protein assembly provides a means to regulate function. Supramolecular building blocks, including rigid macrocycles, are versatile triggers of protein assembly. Now it is shown that sulfonato‐calix[8]arene (sclx8) mediates the formation of cytochrome c tetramers in solution. This tetramer spontaneously disassembles at ≥2 equivalents of sclx8, providing a remarkable example of auto‐regulation. Using X‐ray crystallography the sclx8 binding sites on cytochrome c were characterized. Crystal structures at different protein–ligand ratios reveal varying degrees (up to 35 %) of protein surface coverage by the flexible calixarene and suggest a mechanism for oligomer disassembly. The solution structure of the oligomer was characterized by small‐angle X‐ray scattering. Overall, the data indicate calixarene‐controlled protein assembly and disassembly without the requirement for a competitive inhibitor, and point to protein encapsulation by a flexible macrocycle. Calixarene‐controlled assembly and disassembly of a protein tetramer is demonstrated. The flexible sulfonato‐calix[8]arene acts as a scaffold for the assembly of cytochrome c. High concentrations of the calixarene mask the protein surface and prevent oligomerization, providing a means to control assembly without the need for competitive inhibitors. [ABSTRACT FROM AUTHOR]

Abstract: Here, we provide the first structural characterization of host–guest complexation between cucurbit[7]uril (Q7) and dimethyllysine (KMe2) in a model protein. Binding was dominated by complete encapsulation of the dimethylammonium functional group. While selectivity for the most sterically accessible dimethyllysine was observed both in solution and in the solid state, three different modes of Q7‐KMe2 complexation were revealed by X‐ray crystallography. The crystal structures revealed also entrapped water molecules that solvated the ammonium group within the Q7 cavity. Remarkable Q7‐protein assemblies, including inter‐locked octahedral cages that comprise 24 protein trimers, occurred in the solid state. Cucurbituril clusters appear to be responsible for these assemblies, suggesting a strategy to generate controlled protein architectures. [ABSTRACT FROM AUTHOR]