The importance of vicinal cysteines, C1669 and C1670, for von Willebrand factor A2 domain function.
The von Willebrand factor (VWF) A2 crystal structure has revealed the presence of a rare vicinal disulfide bond between C1669 and C1670, predicted to influence domain unfolding required for proteolysis by ADAMTS13. We prepared VWF A2 domain fragments with (A2-VicCC, residues 1473-1670) and without the vicinal disulfide bond (A2-DeltaCC, residues 1473-1668). Compared with A2-DeltaCC, A2-VicCC exhibited impaired proteolysis and also reduced binding to ADAMTS13. Circular dichroism studies revealed that A2-VicCC was more resistant to thermal unfolding than A2-DeltaCC. Mutagenesis of C1669/C1670 in full-length VWF resulted in markedly increased susceptibility to cleavage by ADAMTS13, confirming the important role of the paired vicinal cysteines in VWF A2 domain stabilization.
Luken
Brenda M
BM
Department of Haematology, Imperial College London, London, UK. b.luken@imperial.ac.uk
Winn
Luke Y N
LY
Emsley
Jonas
J
Lane
David A
DA
Crawley
James T B
JT
D051722:ADAM Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000071120:ADAMTS13 Protein; D019943:Amino Acid Substitution; D003545:Cysteine / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D011485:Protein Binding / Q000502:physiology; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D014841:von Willebrand Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D004220:Disulfides; D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D003545:Cysteine