Reactivity of glutaredoxins 1, 2, and 3 from Escherichia coli shows that glutaredoxin 2 is the primary hydrogen donor to ArsC-catalyzed arsenate reduction.
In Escherichia coli ArsC catalyzes the reduction of arsenate to arsenite using GSH with glutaredoxin as electron donors. E. coli has three glutaredoxins: 1, 2, and 3, each with a classical -Cys-Pro-Tyr-Cys- active site. Glutaredoxin 2 is the major glutathione disulfide oxidoreductase in E. coli, but its function remains unknown. In this report glutaredoxin 2 is shown to be the most effective hydrogen donor for the reduction of arsenate by ArsC. Analysis of single or double cysteine-to-serine substitutions in the active site of the three glutaredoxins indicated that only the N-terminal cysteine residue is essential for activity. This suggests that, during the catalytic cycle, ArsC forms a mixed disulfide with GSH before being reduced by glutaredoxin to regenerate the active ArsC reductase.
Shi
J
J
Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit, Michigan 48201, USA.
Vlamis-Gardikas
A
A
Aslund
F
F
Holmgren
A
A
Rosen
B P
BP
D001149:Arsenates / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D004579:Electron Transport; D004926:Escherichia coli / Q000378:metabolism*; D054477:Glutaredoxins; D006859:Hydrogen / Q000378:metabolism; D010088:Oxidoreductases; D011506:Proteins / Q000378:metabolism*
D001149:Arsenates; D018053:Arsenites; D001426:Bacterial Proteins; D054477:Glutaredoxins; D011506:Proteins; D006859:Hydrogen; D010088:Oxidoreductases; C015001:arsenite; C025657:arsenic acid