BIOCHEMISTRY OF BACTERIAL CELL MEMBRANES

该项目的总体目标是研究通量（包括 小分子穿过细菌的表面层。如 众所周知，病原微生物的多重耐药性正在成为 严重威胁人类健康。最近的研究在我们自己和其他 实验室表明，在许多情况下，这种耐药性是协同的， 两个因素的影响，细胞表面层作为渗透屏障 对于药物的流入（革兰氏阴性菌的外膜或 含有分枝杆菌的细胞壁）和主动多药外排 泵.事实上，对于更先进的抗微生物剂， 酶灭活细菌，如氟喹诺酮类，这种机制 阻止药物到达靶点已经成为一种主要机制 抗战在这项研究中，我们计划继续我们的表征， 这些抵抗机制。因此，我们将表征的“慢”孔蛋白的 生物体如铜绿假单胞菌，蛋白质，有助于 通过减缓细菌的流入， 抗菌剂穿过它们的外膜。我们会研究 分枝杆菌的细胞壁大大减缓了 大多数病原体通过产生分枝菌酸和其他 脂质。另一方面，我们将探讨多药外排的机制 泵，特别是那些显示出令人难以置信的广泛的泵， 特异性，如大肠杆菌的AcrAB，它几乎可以挤出任何 亲脂性或两亲性化合物，包括染料，消毒剂，洗涤剂， 溶剂和几乎所有的抗生素（氨基糖苷类除外）。这些泵 当细菌处于压力下时， 并确定调控途径。最后，作为ABC的原型， 转运蛋白，包括P-糖蛋白和CFTR，麦芽糖转运蛋白 将纯化超嗜热菌激烈火球菌的复合物，因为 来自超嗜热菌的蛋白质倾向于产生衍射良好的晶体， 非常需要获得这类重要的晶体学数据， 运输机

The overall goal of this project is to study the flux (both in and out) of small molecules across the surface layers of bacteria. As is well-known, multiple resistance in pathogenic microorganisms is becoming a serious threat to human health. Recent studies in our own and other laboratories suggest that in many cases such resistance is the synergistic effect of two factors, the cell surface layer acting as permeability barrier for the influx of drugs (outer membrane of Gram-negative bacteria or mycolate-containing cell wall of mycobacteria) and active, multidrug efflux pumps. In fact, for more advanced antimicrobial agents that resist the enzymatic inactivation of bacteria, such as fluoroquinolones, this mechanism that prevents the access of drugs to the target has become a primary mechanism of resistance. In this study, we plan to continue our characterization of both of these resistance mechanisms. Thus we will characterize the "slow" porins of organism such as Pseudomonas aeruginosa, the proteins that contribute to the generalized intrinsic resistance of these bacteria by slowing down the influx of antimicrobial agents across their outer membrane. We will study the mechanism in which the cell wall of mycobacteria drastically slows down the entry of most agents by producing an organized layer of mycolic acid and other lipids. At the other end, we will investigate the mechanism of multidrug efflux pumps, especially those pumps that show an incredibly wide range of specificity, such as AcrAB of Escherichia coli that extrudes almost any lipophilic or amphiphilic compounds, including dyes, disinfectants, detergents, solvents, and practically all antibiotic (except aminoglycosides). These pumps appear to become expressed more strongly when the bacteria are under stress, and the pathway of regulation will be defined. Finally, as a prototype of ABC transporter, which includes P-glycoprotein and CFTR, the maltose transporter complex of a hyperthermophile Pyrococcus furiosus will be purified, because proteins from hyperthermophiles tend to produce well-diffracting crystals, and there is great need to obtain crystallographic data on this important class of transporters.