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Proc Natl Acad Sci U S A. 2002 Jun 25;99(13):8506-11. Epub 2002 Jun 18.

All intermediates of the arsenate reductase mechanism, including an intramolecular dynamic disulfide cascade.

Author information

1
Dienst Ultrastructuur, Vlaams interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Paardenstraat 65, 1640 St. Genesius-Rode, Belgium. jmessens@vub.ac.be

Abstract

The mechanism of pI258 arsenate reductase (ArsC) catalyzed arsenate reduction, involving its P-loop structural motif and three redox active cysteines, has been unraveled. All essential intermediates are visualized with x-ray crystallography, and NMR is used to map dynamic regions in a key disulfide intermediate. Steady-state kinetics of ArsC mutants gives a view of the crucial residues for catalysis. ArsC combines a phosphatase-like nucleophilic displacement reaction with a unique intramolecular disulfide bond cascade. Within this cascade, the formation of a disulfide bond triggers a reversible "conformational switch" that transfers the oxidative equivalents to the surface of the protein, while releasing the reduced substrate.

PMID:
12072565
PMCID:
PMC124290
DOI:
10.1073/pnas.132142799
[Indexed for MEDLINE]
Free PMC Article

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