{Reference Type}: Journal Article
{Title}: Structural conversion of the spidroin C-terminal domain during assembly of spider silk fibers.
{Author}: De Oliveira DH;Gowda V;Sparrman T;Gustafsson L;Sanches Pires R;Riekel C;Barth A;Lendel C;Hedhammar M;
{Journal}: Nat Commun
{Volume}: 15
{Issue}: 1
{Year}: 2024 May 31
{Factor}: 17.694
{DOI}: 10.1038/s41467-024-49111-5
{Abstract}: 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.