Transient glycolytic complexation of arsenate enhances resistance in the enteropathogen Vibrio cholerae

Abstract

The ubiquitous presence of toxic arsenate (As V ) in the environment has virtually raised mechanisms of resistance in all living organisms. Generally, bacterial detoxification of As V relies on its reduction to arsenite (As III ) by ArsC, followed by the export of As III by ArsB. However, how pathogenic species resist this metalloid remains largely unknown. Here, we found that V. cholerae, the etiologic agent of the diarrheal disease cholera, outcompetes other enteropathogens when grown on millimolar concentrations of As V . To do so, V. cholerae uses, instead of ArsCB, the As V -inducible vc1068-1071 operon (renamed var for v ibrio a rsenate r esistance), which encodes the arsenate repressor ArsR, an alternative glyceraldehyde-3-phosphate dehydrogenase, a putative phosphatase, and the As V transporter ArsJ. In addition to Var, V. cholerae induces oxidative stress- related systems to counter ROS production caused by intracellular As V . Characterization of the var mutants suggested these proteins function independently from one another and play critical roles in preventing deleterious effects on the cell membrane potential and growth derived from the accumulation As V . Mechanistically, we demonstrate that V. cholerae complexes As V with the glycolytic intermediate 3-phosphoglycerate into 1-arseno-3-phosphoglycerate (1As3PG). We further show that 1As3PG is not transported outside the cell; instead, it is subsequently dissociated to enable extrusion of free As V through ArsJ. Collectively, we propose the formation of 1As3PG as a transient metabolic storage of As V to curb the noxious effect of free As V . This study advances our understanding of As V resistance in bacteria and underscores new points of vulnerability that might be an attractive target for antimicrobial interventions.