|Title||All intermediates of the arsenate reductase mechanism, including an intramolecular dynamic disulfide cascade.|
|Publication Type||Journal Article|
|Year of Publication||2002|
|Authors||Messens, J., J. C. Martins, K. Van Belle, E. Brosens, A. Desmyter, M. De Gieter, J-M. Wieruszeski, R. Willem, L. Wyns, and I. Zegers|
|Journal||Proc Natl Acad Sci U S A|
|Date Published||2002 Jun 25|
|Keywords||Arsenates, 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|
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.
|Alternate Journal||Proc. Natl. Acad. Sci. U.S.A.|
|PubMed Central ID||PMC124290|
All intermediates of the arsenate reductase mechanism, including an intramolecular dynamic disulfide cascade.