Borremans B, Hobman J L, Provoost A, Brown N L, van Der Lelie D
VITO, Vlaamse Instelling voor Technologisch Onderzoek, Environmental Technology Centre, Boeretang 200, 2400 Mol, Belgium.
J Bacteriol. 2001 Oct;183(19):5651-8. doi: 10.1128/JB.183.19.5651-5658.2001.
The lead resistance operon, pbr, of Ralstonia metallidurans (formerly Alcaligenes eutrophus) strain CH34 is unique, as it combines functions involved in uptake, efflux, and accumulation of Pb(II). The pbr lead resistance locus contains the following structural resistance genes: (i) pbrT, which encodes a Pb(II) uptake protein; (ii) pbrA, which encodes a P-type Pb(II) efflux ATPase; (iii) pbrB, which encodes a predicted integral membrane protein of unknown function; and (iv) pbrC, which encodes a predicted prolipoprotein signal peptidase. Downstream of pbrC, the pbrD gene, encoding a Pb(II)-binding protein, was identified in a region of DNA, which was essential for functional lead sequestration. Pb(II)-dependent inducible transcription of pbrABCD from the PpbrA promoter is regulated by PbrR, which belongs to the MerR family of metal ion-sensing regulatory proteins. This is the first report of a mechanism for specific lead resistance in any bacterial genus.
金属抗性罗尔斯通氏菌（以前称为嗜中温产碱菌）CH34菌株的铅抗性操纵子pbr很独特，因为它兼具与Pb(II)摄取、外排和积累相关的功能。pbr铅抗性基因座包含以下结构抗性基因：(i)pbrT，编码一种Pb(II)摄取蛋白；(ii)pbrA，编码一种P型Pb(II)外排ATP酶；(iii)pbrB，编码一种功能未知的预测整合膜蛋白；(iv)pbrC，编码一种预测的前脂蛋白信号肽酶。在pbrC下游，在一段对功能性铅螯合至关重要的DNA区域中鉴定出了编码Pb(II)结合蛋白的pbrD基因。来自PpbrA启动子的pbrABCD的Pb(II)依赖性诱导转录受PbrR调控，PbrR属于金属离子感应调节蛋白的MerR家族。这是关于任何细菌属中特异性铅抗性机制的首次报道。
