All intermediates of the arsenate reductase mechanism, including an intramolecular dynamic disulfide cascade.
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.
Messens
Joris
J
Dienst Ultrastructuur, Vlaams interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Paardenstraat 65, 1640 St. Genesius-Rode, Belgium. jmessens@vub.ac.be
Martins
José C
JC
Van Belle
Karolien
K
Brosens
Elke
E
Desmyter
Aline
A
De Gieter
Marjan
M
Wieruszeski
Jean-Michel
JM
Willem
Rudolph
R
Wyns
Lode
L
Zegers
Ingrid
I
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
D001149:Arsenates; D016623:Ion Pumps; D009097:Multienzyme Complexes; D013438:Sulfhydryl Compounds; D053501:Arsenite Transporting ATPases