The structure of a triple mutant of pI258 arsenate reductase from Staphylococcus aureus and its 5-thio-2-nitrobenzoic acid adduct

URL:

Keywords:

Abstract:

Structural insights into formation of the complex between the ubiquitous thiol-disulfide oxidoreductase thioredoxin and its oxidized substrate are under-documented owing to its entropical instability. In vitro, it is possible via a reaction with 5,5'-dithiobis-(2-nitrobenzoic acid) to make a stable mixed-disulfide complex between thioredoxin from Staphylococcus aureus and one of its substrates, oxidized pI258 arsenate reductase (ArsC) from S. aureus. In the absence of the crystal structure of an ArsC-thioredoxin complex, the structures of two precursors of the complex, the ArsC triple mutant ArsC C10SC15AC82S and its 5-thio-2-nitrobenzoic acid (TNB) adduct, were determined. The ArsC triple mutant has a structure very similar to that of the reduced form of wild-type ArsC, with a folded redox helix and a buried catalytic Cys89. In the adduct form, the TNB molecule is buried in a hydrophobic pocket and the disulfide bridge between TNB and Cys89 is sterically inaccessible to thioredoxin. In order to form a mixed disulfide between ArsC and thioredoxin, a change in the orientation of the TNB-Cys89 disulfide in the structure is necessary

Notes:

DA - 20040525
IS - 0907-4449 (Print)
LA - eng
PT - Journal Article
PT - Research Support, Non-U.S. Gov't
RN - 0 (Disulfides)
RN - 0 (Ion Pumps)
RN - 0 (Multienzyme Complexes)
RN - 0 (Nitrobenzoates)
RN - 0 (Sulfhydryl Compounds)
RN - 15139-21-6 (thionitrobenzoic acid)
RN - 26062-48-6 (polyhistidine)
RN - 71-00-1 (Histidine)
RN - EC 3.6.3.16 (Arsenite Transporting ATPases)
SB - IM