2LTH: NMR structure of major ampullate spidroin 1 N-terminal domain at pH 5.5

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.
PDB ID: 2LTHDownload
MMDB ID: 115364
PDB Deposition Date: 2012/5/25
Updated in MMDB: 2013/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 2LTH: dimeric; determined by author
Molecular Components in 2LTH
Label Count Molecule
Proteins (2 molecules)
Major Ampullate Spidroin 1
Molecule annotation
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Citing MMDB