ArsD was initially reported to be a trans-acting repressor of the arsRDABC operon, which confers resistance to arsenicals and antimonials in Escherichia coli [1]. It has since been shown to be a metallochaperone that delivers As(III) to ArsA (the c ...
ArsD was initially reported to be a trans-acting repressor of the arsRDABC operon, which confers resistance to arsenicals and antimonials in Escherichia coli [1]. It has since been shown to be a metallochaperone that delivers As(III) to ArsA (the catalytic subunit of the ArsAB pump encoded by arsRDABC), increasing its affinity for As(III) allowing resistance to environmental concentrations of arsenic [2,3]. ArsD has three conserved cysteines Cys(12), Cys(13), and Cys(18), which form a three sulfur-coordinated As(III) binding site that is essential for delivery of As(III) to, and activation of the ArsAB pump [2,3]. This family also includes ArsD homologues which do not contain the conserved CCxxxxC required for function.