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Authors
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Hofmaier, M. ; Malanin, M. ; Bittrich, E. ; Lentz, S. ; Urban, B. ; Scheibel, T. ; Fery, A. ; Müller, M.
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Title
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ß-sheet structure formation within binary blends of two spider silk related peptides
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Date
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12.01.2023
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Number
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61292
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Abstract
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Intrinsically disordered proteins (IDPs) play an important role in molecular biology and medicine because their induced folding can lead to so-called conformational diseases, where ß-amyloids play an important role. Still, the molecular folding process into the different substructures, such as parallel/antiparallel or extended ß-sheet/crossed ß-sheet is not fully understood. The recombinant spider silk protein eADF4(Cx) consisting of repeating modules C, which are composed of a crystalline (pep-c) and an amorphous peptide sequence (pep-a), can be used as a model system for IDP since it can assemble into similar structures. In this work, blend films of the pep-c and pep-a sequences were investigated to modulate the ß-sheet formation by varying the molar fraction of pep-c and pep-a. Dichroic Fourier-transform infrared spectroscopy (FTIR), circular dichroism, spectroscopic ellipsometry, atomic force microscopy, and IR nanospectroscopy were used to examine the secondary structure, the formation of parallel and antiparallel ß-sheets, their orientation, and the microscopic roughness and phase formation within peptide blend films upon methanol post-treatment. New insights into the formation of filament-like structures in these silk blend films were obtained. Filament-like structures could be locally assigned to ß-sheet-rich structures. Further, the antiparallel or parallel character and the orientation of the formed ß-sheets could be clearly determined. Finally, the ideal ratio of pep-a and pep-c sequences found in the fibroin 4 of the major ampullate silk of spiders could also be rationalized by comparing the blend and spider silk protein systems.
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Publisher
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Biomacromolecules
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Wikidata
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Citation
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Biomacromolecules 24 (2023) 825-840
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DOI
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https://doi.org/10.1021/ACS.BIOMAC.2C01266
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Tags
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