BACTERIAL CELL SURFACE STRUCTURE FUNCTIONS & BIOGENESIS

具有共价连接的脂类和脂肪酸的膜脂蛋白 生物膜中无处不在的成分。在细菌中，脂类修饰 蛋白质的氨基末端含有N-酰基甘油酯-半胱氨酸， 被合成为前体蛋白，称为前脂蛋白。 前脂蛋白经历了广泛的翻译后修饰和 处理反应以形成成熟的脂蛋白。细菌的生物发生 细菌中的脂蛋白与其分泌密切相关。我们的 长期目标是研究脂蛋白的生物化学。 成熟，以阐明其输出和组装成 细菌的细胞膜和了解它们的调节 流程。 我们建议继续我们对脂蛋白的生化和遗传学研究 革兰氏阴性和革兰氏阳性细菌的生物发生。我们的特定 目的包括：(1)前脂蛋白的鉴定和性质 通过酶纯化、突变株的分离等方法对酶进行修饰 对活性有缺陷的这些酶进行纯化、分离 这些酶活性有缺陷的突变体及其克隆 编码这些酶的基因；(2)结构、膜的研究 前脂蛋白信号肽(信号肽)的拓扑结构和组装 Ii)在大肠杆菌的细胞膜上；和(3) X-ILES-LSP-orf149-orf316操纵子在大肠杆菌和 其他细菌。 将采用的技术包括分子遗传学、重组DNA 技术基因融合、膜生物化学与细菌生理 学习。

Membrane lipoprotein with covalently linked lipids and fatty acids are ubiquitous components of biological membranes. In bacteria, lipid-modified proteins, which contain N-acyl glyceride-cysteine as the amino terminus, are synthesized as precursor proteins called prolipoproteins. Prolipoproteins undergo extensive posttranslational modification and processing reactions to form the mature lipoproteins. The biogenesis of lipoproteins in bacteria is intimately related to their secretion. Our long-term objectives are to study the biochemistry of lipoprotein maturation, to elucidate its mechanism of export and assembly into the bacterial cell envelope and to understand the regulation of these processes. We propose to continue our biochemical and genetic studies of lipoprotein biogenesis in both gram-negative and gram-positive bacteria. Our specific aims include (1) identification and characterization of prolipoprotein modification enzymes through enzyme purification, isolation of mutants defective in the activities of these enzyme purification, isolation of mutants defective in the activities of these enzymes, and cloning of the genes encoding these enzymes; (2) studies of the structures, membrane topology and assembly of prolipoprotein signal peptidase (signal peptidase II) in the cytoplasmic membrane of Escherichia coli; and (3) characterization of the x-ileS-lsp-orf149-orf316 operon in E. coli and other bacteria. Techniques to be employed include molecular genetics, recombinant DNA technology gene fusion, membrane biochemistry and bacterial physiological studies.