Chrysiogenes arsenatis

Macy JM, K Nuna, KD Hagen, DR Dixon, PJ Harbour, M Cahill, LI Sly (1996) Chrysiogenes arsenatis gen. nov., sp. nov., a new arsenate-respiring bacterium isolated from gold mine wastewater. Int J Syst Bacteriol 46 1153-1157. 

The chlorate reductase has been characterized in strain GR-1 where it was found in the periplasm, is oxygen-sensitive, and contains molybdenum, and both [3Fe-4S] and [4Fe-4S] clusters (Kengen et al. 1999). The arsenate reductase from Chrysiogenes arsenatis contains Mo, Fe, and acid-labile S (Krafft and Macy 1998), and the reductase from Thauera selenatis that is specific for selenate, is located in the periplasmic space, and contains Mo, Fe, acid-labile S, and cytochrome b (Schroeder et al. 1997). In contrast, the membrane-bound selenate reductase from Enterobacter cloacae SLDla-1 that cannot function as an electron acceptor under anaerobic conditions contains Mo and Fe and is distinct from nitrate reductase (Ridley et al. 2006). 

Chrysiogenes arsenatis is the only known organism capable of using acetate as the electron donor and arsenate as the terminal electron acceptor for growth. This reduction of arsenate to arsenite is catalyzed by an inducible respiratory arsenate reductase, which has been isolated and characterized by Kraft and Macy (1998). Arsenate reductase (Arr) from C. arsenatis is a... 

Kraft T, Macy JM. 1998. Purification and characterization of the respiratory arsenate reductase of Chrysiogenes arsenatis. Eur J Biochem. 255 647-53. 

Macy, J.M. and Santini, J.M. (2002) Unique modes of arsenate respiration by Chrysiogenes arsenatis and Desulfomi-crobium sp. str. Ben-RB, in Environmental Chemistry of Arsenic (ed. W.T. Frankenberger Jr.), Marcel Dekker, New York, pp. 297-312. 

AY660883X81319 Chrysiogenes arsenatis strain BAL-1 arrA 16S rRNA Krafft and Macy (1998) Macy et al. (1996)... 

Unique Modes of Arsenate Respiration by Chrysiogenes arsenatis and Desulfomicrobium sp. str. Ben-RB... 

The reduction of arsenate [As(V)] to arsenite [As(III)] is known to occur in anoxic environments (1,2). Until recently, however, the organisms responsible for this reduction were not known. A number of different bacteria have been isolated that are able to respire with arsenate, reducing it to arsenite. With one exception, these organisms use the nonrespiratory substrate lactate as the electron donor (3-6) and are listed in Table 1. Two of them, Desulfotomaculum auripig-mentum str. OREX-4 (7,8) md Desulfomicrobium sp. str. Ben-RB (9), also respire with sulfate as the terminal electron acceptor. None are able to use the respiratory substrate acetate as the electron donor for arsenate respiration. The only organism known able to do so is Chrysiogenes arsenatis (10). 

This chapter concentrates on arsenate respiration by Chrysiogenes arsenatis and Desulfomicrobium sp. str. Ben-RB. The evidence indicates that they have specific respiratory arsenate reductases involved in energy generation. The isolation, phytogeny, physiology, and biochemistry of arsenate reduction are described separately for each organism. 

Figure 1 Electron micrograph of Chrysiogenes arsenatis. Bar = 1 im. (From Ref. 10.)...

Figure 3 Sequence alignment of the N-termini of ArrA and molybdenum-containing proteins. The sequences belong to the arsenate reductase of Chrysiogenes arsenatis C.a ArrA) (14), the polysulfide reductase of WoUnella succinogenes (Wii. PsrA), and the periplasmic nitrate reductases of Escherichia coli (E.c. NapA) and Pseudomonas sp. G-179 P.s. sp. NapA). Boxed amino acids show identity to C. arsenatis ArrA.

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