BIOSYNTHESIS OF BACTERIAL CELL WALLS AND MEMBRANES

细菌细胞壁和细胞膜的生物合成

• 批准号: 3124217
• 负责人: GERALD D SHOCKMAN
• 金额: $ 21.22万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-01-01 至 1993-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3124217
• 关键词: Enterococcus; antibacterial agents; autoradiography; cell cycle; cell membrane; cell wall; electron microscopy; exo alpha sialidase; membrane reconstitution /synthesis; microorganism growth; microorganism metabolism; nucleic acid inhibitor; penicillins; peptidoglycan; protein biosynthesis; radiotracer; streptomycin

We will continue to study aspects of the biosynthesis, assembly and degradation of the bacteria cell wall, especially in relationship to cell growth and cell division. Emphasis will be placed on studies of Streptococcus faecium ATCC 9790 as a "model system," particularly because of its relatively simple shape and mode of division. Studies during the next 5-year grant period will be directed towards studies of the possible roles of two separate and distinct muramidases of SF in surface assembly and division. Thus we propose to: (i) Study several of the properties of the two very unusual autolytic murasidases of SF. Included will be studies of the molecular mechanism of hydrolysis of PGs by muramidase-2 (E- 2). The possibility that E-2 is a transglycosidase is of particular interest, as is the possibility that E-2 is a "two- headed" type of transglycosidase-transpeptidase, similar to at least two of the penicillin-binding proteins (PBPs) of Escherichia coli. Additionally we will study and compare the binding of and catalytic properties of both E-l and E-2 on a number of different soluble and insoluble substrates. The ultimate goal of these studies is to obtain an insight into the action of and regulation of these two activities in growing and dividing bacteria. (ii) Study the possible in vivo functions of these two, redundant, PG hydrolases in cell wall assembly, surface enlargement and/or cell division. Towards this goal we will obtain and characterize isogenic pairs, one of which will contain a mutation in the structural gene for E-1 or E-2. The genes for E-l and E-2 will be cloned in E. coli and the two genes will be sequenced. (iii) Additional studies will include investigations of the relationship of E-2 to PBPs, and studies of cell wall organization using monoclonal antibodies to epitopes present in the cell wall PG.

我们将继续研究生物合成，组装和 细菌细胞壁的降解，尤其是在关系中 细胞生长和细胞分裂。 重点将放在 粪链球菌ATCC 9790作为“模型系统”的研究， 特别是因为它相对简单的形状和模式 分配。 在接下来的5年赠款期内的研究将是 针对研究两个独立和 SF在表面组装和分裂中的不同杂种酶。 因此 我们建议：（i）研究两者的几个特性 SF的不寻常的自溶性穆拉西德酶。 包括 Muramidase-2（E- 2）。 E-2是持续糖苷酶的可能性是 特别兴趣，E-2是“两者的可能性 头部的“类糖苷酶 - 转肽酶类型，类似于AT 至少两种埃切里希菌的青霉素结合蛋白（PBP） 大肠杆菌。 此外，我们将研究和比较和比较 E-L和E-2的催化特性在许多不同的 可溶性和不溶性底物。 这些的最终目标 研究是为了深入了解和调节的作用和调节 在生长和分裂细菌的这两个活动中。 （ii） 研究这两个，多余的PG的体内功能 细胞壁组件中的水解酶，表面增大和/或细胞 分配。 达到这个目标，我们将获得并描述 等生对，其中之一将包含一个突变 E-1或E-2的结构基因。 E-L和E-2的基因将是 克隆在大肠杆菌中，两个基因将进行测序。 （iii） 其他研究将包括对关系的研究 E-2至PBP的研究以及使用的细胞壁组织研究 细胞壁pg中存在的表位的单克隆抗体。