Does DsbA Have Chaperone-like Activity?

DsbA showed chaperone-like activity similar to but weaker than that of protein disulfide isomerase in increasing reactivation and decreasing aggregation during the refolding of guanidine hydrochloride-denaturedd-glyceraldehyde-3-phosphate dehydrogenase and rhodanese. The fact that both enzymes are devoid of disulfide bonds indicates the independence of the chaperone-like activity of DsbA from its thiol–protein oxidoreductase activity. The increased reactivation ofd-glyceraldehyde-3-phosphate dehydrogenase by DsbA can be suppressed with increasing concentrations of a peptide of 21 amino acid residues, suggesting that the peptide binding ability of DsbA is responsible for its chaperone-like activity.