BACTERIAL CELL SURFACE STRUCTURE FUNCTIONS & BIOGENESIS

细菌细胞表面结构功能

• 批准号: 2175280
• 负责人: PAUL D RICK
• 金额: $ 38.12万
• 依托单位: HENRY M. JACKSON FDN FOR THE ADV MIL/MED
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-08-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2175280
• 关键词: Escherichia coli; Salmonella typhimurium; acylation; apolipoproteins; bacterial proteins; copper; ion transport; ligase; metal metabolism; nonblood lipoprotein; peptidoglycan; protein biosynthesis; protein purification; protein structure function

DESCRIPTION: (adapted from investigator's abstract) A rapidly increasing number of membrane proteins in bacteria have been found to contain an N- terminal lipoamino acid, N-acyl-diacylglycerylcysteine, the hallmark of all bacterial lipoproteins. As of 1993, more than 130 lipoproteins have been identified in both gram positive and gram negative bacteria covering a wide spectrum of genera and species. The biosynthesis of lipoproteins in bacteria is both temporally and spatially related to the export of these membrane proteins across the cytoplasmic membranes. These proteins are made as precursor proteins with N-terminal signal sequences which contain a "lipobox" sequence at the junction of the signal sequences and the mature proteins. Following the interaction of the precursor proteins with the export machinery defined by the SecA, SecY SecD and SecF proteins, the prolipoproteins are modified and processed by three enzymes located in the cytoplasmic membrane. These three enzymes are prolipoprotein diacylglyceral transferase, prolipoprotein signal peptidase and apolipoprotein N- acyltransferase encoded by the lgt, lsp, and lnt genes, respectively, in Escherichia coli and Salmonella typhimurium. Mutants defective in any of these three genes are conditionally lethal. In addition, lnt mutants are also copper sensitive, and the lnt gene is allelic with the cutE gene, one of six genes postulated to be involved in copper transport and homeostasis in E. coli. Using the E. coli major outer membrane lipoprotein as the model system, the investigator proposes; (i) to elucidate the biochemical basis for the essential nature of the lipoprotein biosynthetic pathway in E. coli or S. typhimurium; (ii) to identify the gene encoding lipoprotein:peptidoglycan ligase in E. coli; (iii) to study the structure, function and assembly of the prolipoprotein modification and processing enzymes; and (iv) to study the interrelationship between apolipoprotein N-acylation and the transport and homeostasis of divalent cations such as Cu++ in E. coli. The results of the proposed studies will provide new information regarding the structures, functions and biogenesis of lipoproteins in bacteria. These studies will also provide a rational basis for the search or design of antibacterial agents which utilize the enzymes of this pathway as targets.

描述：（改编自研究者摘要） 已经发现细菌中越来越多的膜蛋白 含有N-末端脂氨基酸，N-酰基-二酰基甘油半胱氨酸， 所有细菌脂蛋白的标志。 截至1993年，超过130 脂蛋白在革兰氏阳性和革兰氏阳性细胞中均已被鉴定， 阴性细菌覆盖广泛的属和种。 的 细菌中脂蛋白的生物合成是暂时的， 空间上与这些膜蛋白跨膜的输出相关， 细胞质膜 这些蛋白质作为前体蛋白质 具有N-末端信号序列，所述N-末端信号序列在 信号序列和成熟蛋白质的连接处。 以下 前体蛋白与输出机制的相互作用 由SecA、SecY、SecD和SecF蛋白定义，前脂蛋白是 由位于细胞质中的三种酶修饰和加工 膜的 这三种酶是前脂蛋白二酰甘油 转移酶、前脂蛋白信号肽酶和载脂蛋白N- 分别由LGT、LSP和LNT基因编码的酰基转移酶， 在大肠杆菌和鼠伤寒沙门氏菌中。 任何突变体都有缺陷 这三个基因中的一个是条件致死的。 此外，lnt突变体 也是铜敏感的，并且lnt基因与cutE等位 基因，假设参与铜转运的六个基因之一， E.杆菌 使用E. coli主要外膜脂蛋白为模型体系， 研究者建议：（i）阐明生物化学基础， E.脂蛋白生物合成途径的本质。杆菌 或s 鼠伤寒沙门氏菌;（ii）鉴定编码 脂蛋白：大肠杆菌中的肽聚糖连接酶。（iii）研究 前脂蛋白修饰的结构、功能和组装， 加工酶;和（iv）研究之间的相互关系 载脂蛋白N-酰化与二价 阳离子如E中的Cu++。杆菌 拟议研究的结果 将提供有关结构、功能和 细菌中脂蛋白的生物发生。 这些研究还将提供 为抗菌剂的研究或设计提供了合理的基础， 利用该途径的酶作为靶标。