Rosen B P, Bhattacharjee H, Shi W
Department of Biochemistry, Wayne State University, School of Medicine, Detroit, Michigan 48201, USA.
J Bioenerg Biomembr. 1995 Feb;27(1):85-91. doi: 10.1007/BF02110335.
The ars (arsenical resistance) operon cloned from R-factor R773 has five genes that encode two repressor proteins, ArsR and ArsD, and three structural proteins, ArsA, ArsB, and ArsC. The ArsA and ArsB proteins form a membrane-bound pump that functions as an oxyanion-translocating ATPase. The substrates of the pump are the oxyanions arsenite or antimonite. The ArsC protein is an arsenate reductase that reduces arsenate to arsenite, which is subsequently pumped out of the cell. This review deals with the mechanism of transcriptional regulation by the ArsR repressor and allosteric regulation of the ArsA protein, the catalytic subunit of the pump. The chemical nature of the inducer plays an important role in regulation. In solution arsenite or antimonite exist as oxyanions and reacts with the cysteines in proteins. In both transcriptional regulation by the ArsR repressor and allosteric regulation of the ArsA ATPase, the ability of As(III) and Sb(III) to interact with the cysteines of the proteins, involves their action as effector.
从R因子R773克隆的抗砷（ars）操纵子有五个基因，编码两种阻遏蛋白ArsR和ArsD，以及三种结构蛋白ArsA、ArsB和ArsC。ArsA和ArsB蛋白形成一种膜结合泵，作为一种氧阴离子转运ATP酶发挥作用。该泵的底物是氧阴离子亚砷酸盐或亚锑酸盐。ArsC蛋白是一种将砷酸盐还原为亚砷酸盐的砷酸盐还原酶，随后亚砷酸盐被泵出细胞。本综述探讨了ArsR阻遏蛋白的转录调控机制以及该泵的催化亚基ArsA蛋白的变构调节。诱导剂的化学性质在调控中起重要作用。在溶液中，亚砷酸盐或亚锑酸盐以氧阴离子形式存在，并与蛋白质中的半胱氨酸反应。在ArsR阻遏蛋白的转录调控和ArsA ATP酶的变构调节中，As(III)和Sb(III)与蛋白质半胱氨酸相互作用的能力涉及其作为效应物的作用。
