METAL BINDING DOMAINS IN METALLOREGULATORY PROTEINS

金属调节蛋白中的金属结合域

• 批准号: 6373879
• 负责人: BARRY P. ROSEN
• 金额: $ 29.14万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6373879
• 关键词: DNA binding protein; DNA footprinting; X ray spectrometry; antibiotics; arsenic; bacterial genetics; bactericidal immunity; binding sites; cadmium; copper; drug resistance; gene induction /repression; mass spectrometry; metalloproteins; operon; stoichiometry; transcription factor

The goal of this project is determination of the structure of the metal binding sites that form the inducer binding domains of transcriptional repressors that regulate plasmid-encoded bacterial resistances. In common with many drug and antibiotic resistances, the arsenical (ars) and cadmium (cad) resistance operons encode transport ATPases for the extrusion of As(III)/Sb(III) or Pb(II)/Cd(II)/Zn(II). The ArsR and CadC repressors are two small homologous metalloregulatory proteins responsible for metal-regulated gene expression of the ars and cad operons. Residues required for each inducer binding domain will be determined. In addition, in ars operons there is a second As(III)/Sb(III)-responsive repressor, ArsD, which does not exhibit homology to any known metal binding protein. ArsR and ArsD form a regulatory circuit that senses both low and high concentrations of environmental metalloid. The residues involved in As(III)/Sb(III) binding to ArsD will be determined. Finally, the copper (copA) resistance gene encodes a Cu(I)-translocating P-type ATPase. Expression of copA is regulated by copper or silver. The putative CopR regulatory protein will be identified and characterized. Our studies will define new classes of metal binding motifs. This may be more general applicability, since nearly all transport-related drug resistances are transcriptionally regulated, and the drug binding motifs of the regulatory proteins are largely unknown. Thus the repressors of the genes for these efflux pumps provide good model systems for the study of regulation of transmissible bacterial antibiotic resistances.

该项目的目标是确定金属结合位点的结构，这些位点形成转录抑制因子的诱导子结合域，调节质粒编码的细菌耐药性。 与许多药物和抗生素耐药性一样，砷 (ars) 和镉 (cad) 耐药操纵子编码转运 ATP 酶，用于排出 As(III)/Sb(III) 或 Pb(II)/Cd(II)/Zn（二）。 ArsR 和 CadC 阻遏蛋白是两种小的同源金属调节蛋白，负责 ars 和 cad 操纵子的金属调节基因表达。 将确定每个诱导物结合结构域所需的残基。 此外，ars 操纵子中还有第二个 As(III)/Sb(III) 响应阻遏蛋白 ArsD，它与任何已知的金属结合蛋白均不表现出同源性。 ArsR 和 ArsD 形成一个调节电路，可感应低浓度和高浓度的环境类金属。 将测定 As(III)/Sb(III) 与 ArsD 结合所涉及的残基。 最后，铜 (copA) 抗性基因编码 Cu(I) 易位 P 型 ATP 酶。 copA 的表达受铜或银调节。 假定的 CopR 调节蛋白将被鉴定和表征。我们的研究将定义新类别的金属结合基序。这可能具有更普遍的适用性，因为几乎所有与转运相关的耐药性都是转录调节的，并且调节蛋白的药物结合基序很大程度上是未知的。 因此，这些外排泵基因的抑制因子为研究可传播细菌抗生素耐药性的调节提供了良好的模型系统。