MUROPEPTIDE RECYCLING PATHWAY & BETA LACTAMASE INDUCTION

胞肽回收途径

• 批准号: 6386084
• 负责人: JAMES T PARK
• 金额: $ 19.35万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6386084
• 关键词: Escherichia coli; N acetylglucosaminidase; X ray crystallography; bacterial proteins; beta lactamase; biological signal transduction; cell wall; chemical binding; enzyme biosynthesis; enzyme induction /repression; enzyme structure; enzyme substrate; intracellular transport; microorganism metabolism; permease; protein transport

Uptake of cell wall degradation products via the muropeptide recycling pathway is required for induction of beta-lactamase. The MppA permease pathway for import of free murein tripeptide affects multidrug resistance so that a full understanding of these pathways has important implications for health. The broad, long-term objective of this research is to characterize the murein tripeptide recycling pathway and the Mpp permease, a new periplasmic binding-protein dependent permease pathway specific for murein tripeptide. We hypothesize that both the recycling pathway and the Mpp permease pathway have a monitoring function to signal changes in the condition of the cell wall so that the cell can respond to the changes appropriately. In addition to exploring these hypotheses, the proposed research will extend our understanding of the recycling pathway by characterizing the AmpG permease and the NagZ beta-N-acetylglucosaminidase and of the MppA permease pathway by determining its specificity and that of MppA itself. Specific aims: Aim 1: a. To determine the substrate specificity of AmpG permease, a permease required for murein recycling and beta-lactamase induction. b. To determine if NagZ beta-N-acetylglucosaminidase is needed to form the inducer for beta-lactamase and to determine the substrate specificity of NagZ. Aim 2: To determine if the recycling pathway is involved in signaling to the cell that its cell wall is being damaged. Aim 3: To determine the binding specificity of MppA and its binding constants for the murein tripeptide, L- Ala-gamma-D-Glu-meso-Dap and other tripeptides whose importation is facilitated by MppA. Aim 4: To determine if MppA is involved in signaling which is strongly suggested by several observations described in the progress report. Aim 5: To determine the crystal structure of MppA. Aim 6: To determine if groESL is required for export of MppA and OppA to the periplasm.

通过胞肽再循环途径摄取细胞壁降解产物是诱导β-内酰胺酶所必需的。MppA通透酶途径的进口自由murein三肽影响多药耐药性，使这些途径的充分了解有重要意义的健康。 这项研究的广泛，长期的目标是表征的murein三肽回收途径和Mpp通透酶，一种新的周质结合蛋白依赖性通透酶途径特异性的murein三肽。 我们假设，回收途径和Mpp通透酶途径都具有监测功能，可以发出细胞壁状况变化的信号，以便细胞能够适当地响应变化。 除了探索这些假设，拟议的研究将扩大我们的理解，通过表征AmpG通透酶和NagZ β-N-乙酰氨基葡萄糖苷酶和MppA通透酶途径，通过确定其特异性和MppA本身的再循环途径。具体目标：目标1：a.确定AmpG通透酶的底物特异性，该通透酶是胞壁素再循环和β-内酰胺酶诱导所需的通透酶。 B.确定是否需要NagZ β-N-乙酰氨基葡萄糖苷酶来形成β-内酰胺酶的诱导剂，并确定NagZ的底物特异性。 目的2：确定循环途径是否参与向细胞发出细胞壁受损的信号。目标三：确定MppA的结合特异性及其对胞壁素三肽、L-Ala-γ-D-Glu-meso-Dap和其他三肽的结合常数，所述三肽的输入由MppA促进。 目的4：确定MppA是否参与进展报告中描述的几个观察结果强烈建议的信号传导。 目的5：确定MppA的晶体结构. 目的6：确定MppA和OppA输出到周质是否需要groESL。