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

TitleAll intermediates of the arsenate reductase mechanism, including an intramolecular dynamic disulfide cascade.
Publication TypeJournal Article
Year of Publication2002
AuthorsMessens, J., J. C. Martins, K. Van Belle, E. Brosens, A. Desmyter, M. De Gieter, J-M. Wieruszeski, R. Willem, L. Wyns, and I. Zegers
JournalProc Natl Acad Sci U S A
Volume99
Issue13
Pagination8506-11
Date Published2002 Jun 25
ISSN0027-8424
KeywordsArsenates, Arsenite Transporting ATPases, Catalysis, Gram-Positive Bacteria, Ion Pumps, Kinetics, Models, Molecular, Multienzyme Complexes, Mutagenesis, Site-Directed, Nuclear Magnetic Resonance, Biomolecular, Protein Conformation, Sulfhydryl Compounds
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.

DOI10.1073/pnas.132142799
Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID12072565
PubMed Central IDPMC124290
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