title: The importance of vicinal cysteines, C1669 and C1670, for von Willebrand factor A2 domain function.
abstract: 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.
authors.affiliation: Department of Haematology, Imperial College London, London, UK. b.luken@imperial.ac.uk
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Luken
authors.forename: Luke Y N
authors.initials: LY
authors.lastname: Winn
authors.forename: Jonas
authors.initials: J
authors.lastname: Emsley
authors.forename: David A
authors.initials: DA
authors.lastname: Lane
authors.forename: James T B
authors.initials: JT
authors.lastname: Crawley
mesh_terms: 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
chemical_list: D004220:Disulfides; D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D003545:Cysteine