Protein Family Models

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. [1]. 11980902. Evidence for cooperativity between the four binding sites of. dimeric ArsD, an As(III)-responsive transcriptional regulator.. Li S, Rosen BP, Borges-Walmsley MI, Walmsley AR;. J Biol Chem 2002;277:25992-26002.. [2]. 17439954. ArsD residues Cys12, Cys13, and Cys18 form an As(III)-binding. site required for arsenic metallochaperone activity.. Lin YF, Yang J, Rosen BP;. J Biol Chem. 2007;282:16783-16791.. [3]. 21188475. The ArsD As(III) metallochaperone.. Ajees AA, Yang J, Rosen BP;. Biometals. 2011;24:391-399. (from Pfam)

Date:

2024-08-14

arsenic metallochaperone ArsD family protein such as the arsenical resistance operon trans-acting repressor ArsD

Date:

2020-05-01

ArsD, previously widely viewed as a transcriptional regulator involved in arsenic (and antimony) resistance, is now recognized as a metallochaperone that helps pass arsenite, which is As(III), to ArsA, a component of the arsenite/antimonite efflux pump. A motif CCxxxxC near the amino terminus mediates binding to arsenic atoms, but most ArsD have one or two additional pairs of adjacent Cys residues near the C-terminal end of the protein.

Gene:

arsD

Date:

2021-09-10