Correspondence to J. M. Macy, Department of Microbiology, La Trobe University, Bundoora, VIC 3083, Australia
Purification and characterization of the respiratory arsenate reductase of Chrysiogenes arsenatis
Article first published online: 25 DEC 2001
European Journal of Biochemistry
Volume 255, Issue 3, pages 647–653, August (I) 1998
How to Cite
Krafft, T. and Macy, J. M. (1998), Purification and characterization of the respiratory arsenate reductase of Chrysiogenes arsenatis. European Journal of Biochemistry, 255: 647–653. doi: 10.1046/j.1432-1327.1998.2550647.x
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Abbreviations. Arr, respiratory arsenate reductase; ArrA, large subunit of the respiratory arsenate reductase; ArrB, small subunit of the respiratory arsenate reductase; HIC, hydrophobic interaction chromatography; MoCo, molybdenum cofactor.
- Issue published online: 25 DEC 2001
- Article first published online: 25 DEC 2001
- (Received 2 April 1998)
- Cited By
- respiratory arsenate reductase;
- arsenate respiration;
- Chrysiogenes arsenatis.
Chrysiogenes arsenatis is the only bacterium known that respires anaerobically using arsenate as the terminal electron acceptor and the respiratory substrate acetate as the electron donor. During growth, the arsenate is reduced to arsenite; the reduction is catalyzed by an arsenate reductase. This study describes the purification and characterization of a respiratory arsenate reductase (Arr). The enzyme consists of two subunits with molecular masses of 87 kDa (ArrA) and 29 kDa (ArrB), and is a heterodimer α1β1 with a native molecular mass of 123 kDa. The arsenate reductase contains molybdenum, iron, acid-labile sulfur and zinc as cofactor constituents. The Km of the enzyme for arsenate is 0.3 mM and the Vmax is 7013 μmol arsenate reduced min−1 mg protein−1. Nitrate, sulfate, selenate and fumarate cannot serve as alternative electron acceptors for the arsenate reductase. Synthesis of the protein is regulated, as arsenate must be present during growth for the enzyme to be fully induced. The N-terminus of ArrA is similar to a number of procaryotic molybdenum-containing polypeptides (e.g. the formate dehydrogenases H and N of Escherichia coli). The N-terminus of ArrB is similar to iron-sulfur proteins. The respiratory arsenate reductase of C. arsenatis is different from the non-respiratory arsenate reductases of E. coli and Staphylococcus aureus.