Novel Pathway for Arsenic Detoxification in the Legume Symbiont Sinorhizobium meliloti

• DOI: 10.1128/jb.187.20.6991-6997.2005
• Publication Date: 2005-09-30T16:23:42Z
• Authors: Hung-Chi Yang; Jiujun Cheng; Turlough M. Finan; Barry P. Rosen; Hiranmoy Bhattach...
• Keywords: Sinorhizobium meliloti

We report a novel pathway for arsenic detoxification in the legume symbiont Sinorhizobium meliloti. Although majority of ars operons consist three genes, arsR (transcriptional regulator), arsB [As(OH)3/H+ antiporter], and arsC (arsenate reductase), S. meliloti operon includes an aquaglyceroporin (aqpS) place arsB. The presence AqpS resistance is interesting, since channels have previously been shown to adventitiously facilitate uptake arsenite into cells, rendering them sensitive arsenite. To understand role aqpS resistance, were disrupted individually. Disruption resulted increased tolerance but not arsenate, while cells with disruption showed selective sensitivity arsenate. results transport experiments intact suggest that only protein facilitates Coexpression strain E. coli lacking complemented arsenate sensitivity. These imply that, when exposed environmental enters cell through phosphate systems reduced by ArsC. Internally generated flows out downhill movement AqpS. Thus, confers together ArsC-catalyzed reduction. This first physiological function resistance.