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Arsenical resistance operon protein ArsD ArsD was initially reported to be a trans-acting repressor of the arsRDABC operon, which confers resistance to arsenicals and antimonials in Escherichia coli. 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. 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. This family also includes ArsD homologs which do not contain the conserved CCxxxxC required for function. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",