STRUCTURAL STUDIES OF MULTIDRUG BINDING AND TRANSCRIPTION ACTIVATION BY BMRR

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。细菌多药耐药（mdr）是一种严重的健康风险，因为越来越多的人类病原体对目前可用的治疗方法表现出耐药性。多药耐药的一种机制是通过多药外排转运体从细胞中输出有毒化合物。这些膜蛋白已被证明可以结合并排出一系列结构和化学上不同的化合物。这些转运体如何识别和清除药物的分子细节尚不完全清楚，部分原因是与纯化和结晶固有膜蛋白相关的困难。然而，越来越多的蛋白质已经被确定，它们调节多药转运蛋白的表达，以响应转运蛋白挤出的相同有毒化合物。这些转录调节因子更适合于结构和生化研究，因为它们是可溶性的细胞质蛋白，可以更容易地纯化，并且在结构和生化研究中所需的数量也更大。其中一种来自枯草芽孢杆菌的转录调节剂BmrR（细菌多药耐药调节剂）通过结合大量结构不同的亲脂性阳离子化合物（其中许多是bmr的底物）来激活bmr多药转运体基因的转录。在没有药物的情况下，BmrR仍然与bmr启动子结合，并作为抗激活剂起作用。研究BmrR- dna与不同诱导剂分子结合的结构以及多药结合口袋突变体的结构将有助于阐明BmrR识别多种结构不同药物的原理。

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. Bacterial multidrug resistance (mdr) presents a serious health risk as an increasing number of human pathogens are showing resistance to currently available treatments. One mechanism of mdr involves export of toxic compounds from the cell by multidrug efflux transporters. These membrane proteins have been shown to bind to and efflux a diverse array of structurally and chemically dissimilar compounds. The molecular details of how these transporters recognize and expunge drugs is not fully understood, in part due to the difficulty associated with purifying and crystallizing intrinsic membrane proteins. However, a growing number of proteins have been identified that regulate the expression of multidrug transporters in response to the same toxic compounds that the transporters extrude. These transcriptional regulators are much more amenable to structural and biochemical studies as they are soluble, cytosolic proteins which can be purified more easily and in the quantities that are necessary for structural and biochemical studies. One such transcriptional regulator from Bacillus subtilis, BmrR (bacterial multidrug resistance regulator), activates transcription of the bmr multidrug transporter gene by binding to a plethora of structurally dissimilar lipophilic cationic compounds, many of which are substrates of Bmr. In the absence of drug, BmrR remains bound to the bmr promoter and functions as an anti-activator. Structural studies of BmrR-DNA bound to different inducer molecules along with structures of multidrug binding pocket mutants will help to elucidate the principles by which BmrR can recognize multiple structurally dissimilar drugs.