Biochemical characterization of a novel ArsA ATPase complex from Alkaliphilus metalliredigens QYMF

The two putative ars operons in Alkaliphilus metalliredigens QYMF are distinctive in that the arsA gene is split in halves, amarsA1 and amarsA2, and, acr3 but not an arsB gene coexists with arsA. Heterologous expression of one of the A. metalliredigensars operons (ars1) conferred arsenite but not antimonite resistance to ΔarsEscherichia coli. Only the co-expressed AmArsA1 and AmArsA2 displayed arsenite or antimonite stimulated ATPase activity. The results show that AmArsA1–AmArsA2 interaction is needed to form the functional ArsA ATPase. This novel AmArsA1–AmArsA2 complex may provide insight in how it participates with Acr3 in arsenite detoxification.