C‑Terminal Domains of Spider Silk Proteins Having Divergent Structures but Conserved Functional Roles
Spider silk is self-assembled from silk proteins or spidroins. C-terminal domains (CTDs) of various types of spidroins are relatively conserved in amino acid sequences and are suggested to adopt similar structures and perform similar functional roles in spidroin storage and silk formation. Here, we...
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Published in | Biomacromolecules Vol. 23; no. 4; pp. 1643 - 1651 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
11.04.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Spider silk is self-assembled from silk proteins or spidroins. C-terminal domains (CTDs) of various types of spidroins are relatively conserved in amino acid sequences and are suggested to adopt similar structures and perform similar functional roles in spidroin storage and silk formation. Here, we solved the structure of the CTD from a capture-spiral silk protein (CTDFl) and characterized its stability and fibril formation in the presence and absence of a reducing agent at different pH values. CTDFl adopts a dimeric structure with 8 helices, but the CTDs of other types of spidroins exist in a domain-swapped dimeric structure with 10 helices. Despite the structural differences, CTDFl is pH-responsive in stability and fibril formation, similar to the CTDs from minor and major ampullate spidroins. Thus, the functional role of CTDs in silk fiber formation seems conserved. Comparing wild-type CTDFl and its mutants, we found that the pH-responsive behavior results from the protonation of H76, which is conserved from different spider species. In addition, the fibril formation rate of CTDFl correlates with its instability, suggesting that structural changes are involved in fibril formation. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1525-7797 1526-4602 |
DOI: | 10.1021/acs.biomac.1c01513 |