PMID: 20211621
Authors:
Alon A, Heckler EJ, Thorpe C, Fass D
Title:
QSOX contains a pseudo-dimer of functional and degenerate sulfhydryl oxidase domains.
Journal:
FEBS Lett. 2010 Apr 16;584(8):1521-5. Epub 2010 Mar 6.
Abstract:
Quiescin sulfhydryl oxidase (QSOX) catalyzes formation of disulfide bonds between cysteine residues in substrate proteins. Human QSOX1 is a multi-domain, monomeric enzyme containing a module related to the single-domain sulfhydryl oxidases of the Erv family. A partial QSOX1 crystal structure reveals a single-chain pseudo-dimer mimicking the quaternary structure of Erv enzymes. However, one pseudo-dimer "subunit" has lost its cofactor and catalytic activity. In QSOX evolution, a further concatenation to a member of the protein disulfide isomerase family resulted in an enzyme capable of both disulfide formation and efficient transfer to substrate proteins.