title: All intermediates of the arsenate reductase mechanism, including an intramolecular dynamic disulfide cascade.
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.
authors.affiliation: Dienst Ultrastructuur, Vlaams interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Paardenstraat 65, 1640 St. Genesius-Rode, Belgium. jmessens@vub.ac.be
authors.forename: Joris
authors.initials: J
authors.lastname: Messens
authors.forename: José C
authors.initials: JC
authors.lastname: Martins
authors.forename: Karolien
authors.initials: K
authors.lastname: Van Belle
authors.forename: Elke
authors.initials: E
authors.lastname: Brosens
authors.forename: Aline
authors.initials: A
authors.lastname: Desmyter
authors.forename: Marjan
authors.initials: M
authors.lastname: De Gieter
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Wieruszeski
authors.forename: Rudolph
authors.initials: R
authors.lastname: Willem
authors.forename: Lode
authors.initials: L
authors.lastname: Wyns
authors.forename: Ingrid
authors.initials: I
authors.lastname: Zegers
mesh_terms: D001149:Arsenates / Q000378:metabolism; D053501:Arsenite Transporting ATPases; D002384:Catalysis; D006094:Gram-Positive Bacteria / Q000201:enzymology; D016623:Ion Pumps / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D001149:Arsenates; D016623:Ion Pumps; D009097:Multienzyme Complexes; D013438:Sulfhydryl Compounds; D053501:Arsenite Transporting ATPases