MOLECULAR MECHANISMS OF THE MERCURY RESISTANCE SYSTEM

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们建议使用X射线吸收光谱来研究细菌汞抗性系统对重金属解毒的分子机制，该系统由Tn501操纵子编码。MER系统使用金属运输蛋白、用于将汞物种转化和还原为元素挥发性汞(0)的酶，以及一个典型的金属调节系统(基于MERR)，所有这些都显示出对汞的特异性。总的来说，我们感兴趣的是阐明所涉及的分子机制，并研究设计该系统来处理其他重金属(Cd、Au等)的可能性。用于生物修复。这个特殊的程序有两个主要目标：(A)MerR，它与Mero/P和/或RNA聚合酶的相互作用，以及MerD似乎参与缓解MerR激活的作用；(B)MERA(汞还原酶)及其变体，现在已被证明也催化Au(III)还原为Au(I)，最终歧化形成Au(0)胶体。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We propose to use X-ray absorption spectroscopy to study the molecular mechanisms of heavy metal detoxification by the bacterial mercury resistance system, encoded by the Tn501 mer operon. The mer system employs metal transport proteins, enzymes for transformation and reduction of mercury species to elemental volatile Hg(0), and a paradigmatic metalloregulatory system (based on MerR), all of which demonstrate specificity for Hg. In general, we are interested in elucidating the molecular mechanisms involved and in investigating the potential for engineering this system to handle other heavy metals (Cd, Au, etc.) for bioremediation. This particular program has two major targets: (a) MerR, its interactions with merO/P and/or RNA polymerase, and the role of MerD which appears to be involved in relieving MerR activation; (b) MerA (mercuric reductase) and variants that have now been shown to also catalyze the reduction of Au(III) to Au(I), with eventual disproportionation to form Au(0) colloids.