Funktion des CzcCB2A-Transporters

CzcCB2A 转运蛋白的功能

• 批准号: 5141262
• 负责人: Professor Dr. Dietrich H. Nies
• 金额: --
• 依托单位: Institutsbereich Mikrobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 1998
• 资助国家: 德国
• 起止时间: 1997-12-31 至 2006-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5141262?language=en
• 关键词: Funktion; des; CzcCB2A; Transporters

The results obtained during the recent four years show that the CzcCBA transenvelope efflux complex, which catalyzes heavy metal resistance in Ralstonia metallidurans, is working in close interplay with other metal efflux systems. The cationic substrates of CzcCBA Co(II), Zn(II) and Cd(II) may be accepted from the cytoplasm or the periplasm or both compartments. The structure of the central subunit CzcA (RND protein family) of the complex will be solved, additionally, the structure of the related copper transporter CusA. The periplasmic substrate binding sites of either protein will be identified by site-directed mutagenesis. At least for CzcA, the importance of the cytoplasmic metal binding site for the cooperative transport behavior of this protein will be elucidated. Similar experiments will also be performed with the two P-type ATPases from R. metallidurans, ZntA and CadA. Involvement of the other RNDproteins from R. metallidurans for metal resistance in this bacterium will be analyzed. The uptake systems for cobalt, zinc and cadmium of R. metallidurans will be identified by expression in specific E. coli mutant strains. Finally, export of periplasmic cations as a mechanism of detoxification is only reasonable if re-uptake across the outer membrane is somehow limited. Therefore, the role of outer membrane proteins in metal resistance of R. metallidurans will also be evaluated.

近四年的研究结果表明，CzcCBA跨膜外排复合物与其他金属外排系统密切相关，该复合物催化Ralstonia metallidurans对重金属的抗性。CzcCBA Co（II）、Zn（II）和Cd（II）的阳离子底物可以从细胞质或周质或两个隔室接受。该复合物的中心亚基CzcA（RND蛋白家族）的结构将被解决，此外，相关的铜转运蛋白CusA的结构也将被解决。将通过定点诱变鉴定任一蛋白质的周质底物结合位点。至少对于CzcA，细胞质金属结合位点的重要性，这种蛋白质的合作运输行为将得到阐明。类似的实验也将用来自R. metallidurans、ZntA和CadA。R.将分析该细菌中金属耐受性的metallidurans。研究了红球藻对钴、锌、镉的吸收系统。通过在特定的E.大肠杆菌突变株。最后，出口周质阳离子作为一种解毒机制是唯一合理的，如果再吸收跨越外膜是有限的。因此，外膜蛋白在根瘤菌金属抗性中的作用尚不清楚。还将评价金属硬聚糖。