Critical role of a thiolate-quinone charge transfer complex and its adduct form in de novo disulfide bond generation by DsbB.

ABSTRACT: Recent studies have revealed numerous examples in which oxidation and reduction of cysteines in proteins are integrated into specific cascades of biological regulatory systems. In general, these reactions proceed as thiol-disulfide exchange events. However, it is not exactly understood how a disulfide bond is created de novo. DsbB, an Escherichia coli plasma membrane protein, is one of the enzymes that create a new disulfide bond within itself and in DsbA, the direct catalyst of protein disulfide bond formation in the periplasmic space. DsbB is associated with a cofactor, either ubiquinone or menaquinone, as a source of an oxidizing equivalent. The DsbB-bound quinone undergoes transition to a pink (lambdamax, approximately 500 nm, ubiquinone) or violet (lambdamax, approximately 550 nm, men

SUBMITTER: Inaba K 

PROVIDER: S-EPMC1323469 | biostudies-literature | 2006 Jan

REPOSITORIES: biostudies-literature