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Biochemistry of Bacterial Cell Membranes

细菌细胞膜的生物化学

基本信息

批准号：
8808729
负责人：
HIROSHI NIKAIDO
金额：
$ 66.74万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
1976
资助国家：
美国
起止时间：
1976-03-01 至 2018-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8808729
关键词：
Acinetobacter Aminoglycosides Antibiotics Appearance Area Back Bacteria Binding Binding Sites Biochemistry Biological Assay Carbapenems Cell Membrane Permeability Cell Wall Cell membrane Cell surface Cells Clinical Complex Corynebacterium Coupled Development Drug resistance Drug resistance in tuberculosis Escherichia coli Extreme drug resistant tuberculosis Family Fluoroquinolones Genes Genus Mycobacterium Gram-Negative Bacteria Growth Health Japan Kinetics Laboratories Lactams Lead Link Lipids Location Measures Mediating Membrane Micelles Molecular Molecular Conformation Multi-Drug Resistance Mutation Mycobacterium tuberculosis Organism Permeability Pharmaceutical Preparations Play Principal Investigator Process Proteins Proteome Protomer Pseudomonas aeruginosa Public Health Pump Relative (related person)Resistance Role Specificity Substrate Specificity Surface Surveys Transport Process Vesicle antimicrobial drug base cell killing chemotherapeutic agent conformer design disulfide bond efflux pump fight against fluoroquinolone resistance inhibitor/antagonist innovation monomer multi-drug resistant pathogen mycobacterial novel strategies pathogen pathogenic bacteria periplasm porin prevent programs protein folding resistant strain

项目摘要

DESCRIPTION (provided by applicant): The increasing drug resistance among pathogenic bacteria is a major problem. This project is an integrated attempt to study the two general and synergistic mechanisms that bacteria use in order to prevent the access of antibiotics and chemotherapeutic agents to their targets within the bacterial cell. Such drugs must enter the bacterium and bind to the targets in order to inhibit and kill the cell. This process is made difficult by the bacteria by first building a low permeability surface membrane. An outstanding example is the outer membrane of Pseudomonas aeruginosa or Acinetobacter spp, with their exceptionally low-permeability channels or porins. The molecular mechanisms that make the channel protein to show such a low permeability appear to be in the peculiar folding process of these porins, and the project will examine the details of this process. Another example is the mycobacterial outer membrane or cell wall with its unique lipid composition, which makes the entry of lipophilic drugs apparently quite difficult. The project will examine the lipid composition of this membrane in a quantitative manner, and the effect of the lipid composition on permeability. The second mechanism for preventing drug access is the active efflux. Thus, the bacteria can overproduce multidrug efflux pumps of surprisingly wide specificity to actively pump out drugs before they reach the target. The project will examine the AcrB pump of Escherichia coli, which pumps out most of the commonly used antibiotics, with the sole exception of aminoglycosides. It will try to elucidate the path the drug molecule follows inside the large AcrB transporter, and the details of interaction between AcrB and its accessory proteins AcrA and TolC in the adjacent compartments of periplasm and outer membrane. The effect of the presence of drugs on the assembly of AcrB with AcrA and TolC will also be examined. Many of the studies will utilize a covalently linked trimer version of AcrB, so that each component monomer can be fixed in the precise conformation representing a finite step in the transport process. It is hoped that these studies will result in a rather complete and quantitative understanding of the drug entry (and expulsion) process in gram-negative bacteria and mycobacteria, and will help in the design of better antimicrobial agents and also better inhibitors of the efflux pumps.

描述（申请人提供）：病原菌耐药性的增加是一个主要问题。该项目是一个综合的尝试，研究细菌使用的两种一般和协同机制，以防止抗生素和化疗药物进入细菌细胞内的目标。这些药物必须进入细菌并与靶标结合，以抑制和杀死细胞。这个过程是困难的细菌首先建立一个低渗透性的表面膜。一个突出的例子是铜绿假单胞菌或不动杆菌属的外膜，它们具有异常低渗透性的通道或孔蛋白。使通道蛋白表现出如此低的渗透性的分子机制似乎是在这些孔蛋白的特殊折叠过程中，该项目将研究这一过程的细节。另一个例子是分枝杆菌的外膜或细胞壁具有独特的脂质成分，这使得亲脂性药物显然很难进入。该项目将以定量的方式研究这种膜的脂质成分，以及脂质成分对渗透性的影响。第二个防止药物获得的机制是主动外排。因此，细菌可以过度产生具有令人惊讶的广泛特异性的多药物外排泵，以在药物到达靶标之前主动泵出药物。该项目将检查大肠杆菌的AcrB泵，该泵排出大多数常用抗生素，唯一例外的是氨基糖苷类。它将试图阐明药物分子在大AcrB转运蛋白内部的路径，以及AcrB与其辅助蛋白AcrA和TolC在周质和外膜相邻隔室中相互作用的细节。还将检查药物的存在对AcrB与AcrA和TolC的组装的影响。许多研究将利用AcrB的共价连接的三聚体版本，使得每个组分单体可以固定在代表运输过程中有限步骤的精确构象中。希望这些研究将导致对革兰氏阴性菌和分枝杆菌中药物进入（和排出）过程的相当完整和定量的理解，并将有助于设计更好的抗菌剂和更好的外排泵抑制剂。