Structural conversion of the spidroin C-terminal domain during assembly of spider silk fibers.

Autor: De Oliveira, Danilo Hirabae, Gowda, Vasantha, Sparrman, Tobias, Gustafsson, Linnea, Sanches Pires, Rodrigo, Riekel, Christian, Barth, Andreas, Lendel, Christofer, Hedhammar, My
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Zdroj: Nature Communications; 5/31/2024, Vol. 15 Issue 1, p1-14, 14p
Abstrakt: The major ampullate Spidroin 1 (MaSp1) is the main protein of the dragline spider silk. The C-terminal (CT) domain of MaSp1 is crucial for the self-assembly into fibers but the details of how it contributes to the fiber formation remain unsolved. Here we exploit the fact that the CT domain can form silk-like fibers by itself to gain knowledge about this transition. Structural investigations of fibers from recombinantly produced CT domain from E. australis MaSp1 reveal an α-helix to β-sheet transition upon fiber formation and highlight the helix No4 segment as most likely to initiate the structural conversion. This prediction is corroborated by the finding that a peptide corresponding to helix No4 has the ability of pH-induced conversion into β-sheets and self-assembly into nanofibrils. Our results provide structural information about the CT domain in fiber form and clues about its role in triggering the structural conversion of spidroins during fiber assembly. The mechanical properties of spider silk are a consequence of the structural organisation of proteins known as spidroins. Here the authors investigate the structure of the fibers formed by a C-terminal domain of a major spidroin: the study elucidates the mechanisms by which spidroins are transformed from soluble form into a fiber. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index