1RXI: Pi258 Arsenate Reductase (Arsc) Triple Mutant C10sC15AC82S

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.
PDB ID: 1RXIDownload
MMDB ID: 27765
PDB Deposition Date: 2003/12/18
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 1RXI: monomeric; determined by author
Molecular Components in 1RXI
Label Count Molecule
Protein (1 molecule)
Arsenate Reductase(Gene symbol: arsC)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB