Redox-active cysteines of a membrane electron transporter DsbD show dual compartment accessibility.

ABSTRACT: The membrane-embedded domain of the unusual electron transporter DsbD (DsbDbeta) uses two redox-active cysteines to catalyze electron transfer between thioredoxin-fold polypeptides on opposite sides of the bacterial cytoplasmic membrane. How the electrons are transferred across the membrane is unknown. Here, we show that DsbDbeta displays an inherent functional and structural symmetry: first, the two cysteines of DsbDbeta can be alkylated from both the cytoplasm and the periplasm. Second, when the two cysteines are disulfide-bonded, cysteine scanning shows that the C-terminal halves of the cysteine-containing transmembrane segments 1 and 4 are exposed to the aqueous environment while the N-terminal halves are not. Third, proline residues located pseudo-symmetrically around the two cysteine

SUBMITTER: Cho SH 

PROVIDER: S-EPMC1948999 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature