Sequential pH-driven dimerization and stabilization of the N-terminal domain enables rapid spider silk formation
2014 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 5, 3254- p.Article in journal (Refereed) Published
The mechanisms controlling the conversion of spider silk proteins into insoluble fibres, which happens in a fraction of a second and in a defined region of the silk glands, are still unresolved. The N-terminal domain changes conformation and forms a homodimer when pH is lowered from 7 to 6; however, the molecular details still remain to be determined. Here we investigate site-directed mutants of the N-terminal domain from Euprosthenops australis major ampullate spidroin 1 and find that the charged residues D40, R60 and K65 mediate intersubunit electrostatic interactions. Protonation of E79 and E119 is required for structural conversions of the subunits into a dimer conformation, and subsequent protonation of E84 around pH 5.7 leads to the formation of a fully stable dimer. These residues are highly conserved, indicating that the now proposed three-step mechanism prevents premature aggregation of spidroins and enables fast formation of spider silk fibres in general.
Place, publisher, year, edition, pages
Nature Publishing Group, 2014. Vol. 5, 3254- p.
animal; biosynthesis; chemistry; dimerization; genetics; metabolism; nuclear magnetic resonance spectroscopy; pH; spectrofluorometry; spider; static electricity
Biochemistry and Molecular Biology
Research subject Biological Physics
IdentifiersURN: urn:nbn:se:kth:diva-187706DOI: 10.1038/ncomms4254ISI: 000332667600001OAI: oai:DiVA.org:kth-187706DiVA: diva2:931211
FunderDanish National Research FoundationSwedish Research Council
QC 201605272016-05-262016-05-262016-05-27Bibliographically approved