TY - JOUR
T1 - Redox, mutagenic and structural studies of the glutaredoxin/arsenate reductase couple from the cyanobacterium Synechocystis sp. PCC 6803
AU - Kim, Sang Gon
AU - Chung, Jung Sung
AU - Sutton, R. Bryan
AU - Lee, Jong Sun
AU - López-Maury, Luis
AU - Lee, Sang Yeol
AU - Florencio, Francisco J.
AU - Lin, Teresa
AU - Zabet-Moghaddam, Masoud
AU - Wood, Matthew J.
AU - Nayak, Kamakshi
AU - Madem, Vivek
AU - Tripathy, Jatindra N.
AU - Kim, Sung Kun
AU - Knaff, David B.
N1 - Funding Information:
Portions of this research were carried out at the Stanford Synchrotron Radiation Lightsource, a Directorate of SLAC National Accelerator Laboratory and an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Stanford University. The SSRL Structural Molecular Biology Program is supported by the DOE Office of Biological and Environmental Research and by the National Institutes of Health, National Center for Research Resources, Biomedical Technology Program (P41RR001209), and the National Institute of General Medical Sciences.
Funding Information:
This study was supported by grants from the YIDP and URC programs at Baylor University (to S.-K.K.), from a Rural Development Administration for the Next Generation Biogreen 21 Program (SSAC Grant # PJ008109 , to S. Y. L.), BFU2007-06 and BFU2010-15708 from MCINN and FEDER (European Union) and BIO-0284 from Junta de Andalucia (to F.J.F.), from the Robert A. Welch foundation ( D-0710 to D. B. K.) and from the U.S. Department of Energy ( DE-FG03-99ER20346 to D.B.K.). Teresa Lin was a Welch Summer Scholar at Texas Tech University. The authors would like to thank Dr. Franck Chauvat and Dr. Corinne Cassier-Chauvat for helpful discussions.
PY - 2012/2
Y1 - 2012/2
N2 - The arsenate reductase from the cyanobacterium Synechocystis sp. PCC 6803 has been characterized in terms of the redox properties of its cysteine residues and their role in the reaction catalyzed by the enzyme. Of the five cysteines present in the enzyme, two (Cys13 and Cys35) have been shown not to be required for catalysis, while Cys8, Cys80 and Cys82 have been shown to be essential. The as-isolated enzyme contains a single disulfide, formed between Cys80 and Cys82, with an oxidation-reduction midpoint potential (E m) value of - 165 mV at pH 7.0. It has been shown that Cys15 is the only one of the four cysteines present in Synechocystis sp. PCC 6803 glutaredoxin A required for its ability to serve as an electron donor to arsenate reductase, while the other three cysteines (Cys18, Cys36 and Cys70) play no role. Glutaredoxin A has been shown to contain a single redox-active disulfide/dithiol couple, with a two-electron, E m value of - 220 mV at pH 7.0. One cysteine in this disulfide/dithiol couple has been shown to undergo glutathionylation. An X-ray crystal structure, at 1.8 Å resolution, has been obtained for glutaredoxin A. The probable orientations of arsenate reductase disulfide bonds present in the resting enzyme and in a likely reaction intermediate of the enzyme have been examined by in silico modeling, as has the surface environment of arsenate reductase in the vicinity of Cys8, the likely site for the initial reaction between arsenate and the enzyme.
AB - The arsenate reductase from the cyanobacterium Synechocystis sp. PCC 6803 has been characterized in terms of the redox properties of its cysteine residues and their role in the reaction catalyzed by the enzyme. Of the five cysteines present in the enzyme, two (Cys13 and Cys35) have been shown not to be required for catalysis, while Cys8, Cys80 and Cys82 have been shown to be essential. The as-isolated enzyme contains a single disulfide, formed between Cys80 and Cys82, with an oxidation-reduction midpoint potential (E m) value of - 165 mV at pH 7.0. It has been shown that Cys15 is the only one of the four cysteines present in Synechocystis sp. PCC 6803 glutaredoxin A required for its ability to serve as an electron donor to arsenate reductase, while the other three cysteines (Cys18, Cys36 and Cys70) play no role. Glutaredoxin A has been shown to contain a single redox-active disulfide/dithiol couple, with a two-electron, E m value of - 220 mV at pH 7.0. One cysteine in this disulfide/dithiol couple has been shown to undergo glutathionylation. An X-ray crystal structure, at 1.8 Å resolution, has been obtained for glutaredoxin A. The probable orientations of arsenate reductase disulfide bonds present in the resting enzyme and in a likely reaction intermediate of the enzyme have been examined by in silico modeling, as has the surface environment of arsenate reductase in the vicinity of Cys8, the likely site for the initial reaction between arsenate and the enzyme.
KW - Arsenate reductase
KW - Dithiol-disulfide couples
KW - Glutaredoxin
KW - Redox reactions
KW - Synechocystis
UR - http://www.scopus.com/inward/record.url?scp=84455193453&partnerID=8YFLogxK
U2 - 10.1016/j.bbapap.2011.10.012
DO - 10.1016/j.bbapap.2011.10.012
M3 - Article
C2 - 22155275
AN - SCOPUS:84455193453
SN - 1570-9639
VL - 1824
SP - 392
EP - 403
JO - Biochimica et Biophysica Acta - Proteins and Proteomics
JF - Biochimica et Biophysica Acta - Proteins and Proteomics
IS - 2
ER -