Muropeptide Recycling Pathway & Beta Lactamase Induction

胞肽回收途径

• 批准号: 6873160
• 负责人: JAMES T PARK
• 金额: $ 19.11万
• 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 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6873160
• 关键词: Escherichia coli; N acetylglucosamine; alcohol phosphotransferase; bacterial proteins; beta lactamase; biofilm; carbohydrate metabolism; cell wall; enzyme activity; enzyme induction /repression; enzyme structure; microbiology; microorganism metabolism; molecular cloning; peptidoglycan; protein purification; sugar acids

DESCRIPTION (provided by applicant): Amazingly, Escherichia coli degrades over 60% of the murein (peptidoglycan) from its sidewalls each generation and is able to reutilize the components. This process is known as recycling. The goat of this research is to identify and characterize all the enzymes used by E. coli to reutilize cell wall peptidoglycan components. Recycling involves over 10 enzymes that appear to serve no other purpose than to facilitate breakdown and reutilization of murein components. Several outstanding questions remain to be answered in order to have a full understanding of the process. The recycling pathway is required for beta-lactamase induction in many Gram negative organisms and, in addition, we have recently observed that mutations in certain recycling genes result in autoaggregation and biofilm formation. Thus the pathway is of interest in the health related areas of resistance to penicillins and biofilm formation. Specific aims: Aim #1: Determine the pathway for utilization of N-acetylglucosamine in the absence of the N-acetylglucosamine kinase. We have already achieved the original goal of Aim 1, namely, Identify the kinase gene and demonstrate its role in reutilization of N-acetylglucosamine. Aim #2: Determine how E. coli degrades anhydro-N-acetylmuramic acid. Our recent results indicate that a kinase and an etherase may be involved. Hence our current efforts are aimed at purifying these activities in order to identify the genes responsible for the activities. Aim #3: Determine the true inducer of beta-lactamase. Aim #4: Determine how expression of antigen 43 is related to the recycling of murein tripeptide. Antigen 43 causes autoaggregation which facilitates biofilm formation. Deletion of either murein peptide ligase (mpl) or murein peptide amidase A (mpaA) results in production of tripeptide and antigen 43 suggesting that accumulation of the murein tripeptide, L-Ala-gamma-D-Glu-meso-diaminopimelic acid, may be involved.

描述（由申请人提供）：令人惊讶的是，大肠杆菌从其每一代人的侧壁上降解了超过60％的Murein（peptidoglycan），并能够将组件重新升级。这个过程称为回收。这项研究的山羊是识别和表征大肠杆菌用来重新将细胞壁肽聚糖成分重新注射的所有酶。回收涉及10多种酶，这些酶似乎没有其他目的，除了促进穆雷蛋白成分的分解和再利用。为了充分了解该过程，仍有几个杰出的问题要回答。在许多革兰氏阴性生物中，需要回收途径才能进行β-内酰胺酶诱导，此外，我们最近观察到某些回收基因的突变会导致自动录入和生物膜形成。因此，该途径在与健康相关的青霉素和生物膜形成的抗性领域中引起了人们的关注。具体目的：目标＃1：确定在没有N-乙酰基葡萄糖激酶的情况下使用N-乙酰葡萄糖的途径。我们已经实现了AIM 1的最初目标，即确定激酶基因，并证明其在N-乙酰葡萄糖的再利用中的作用。 AIM＃2：确定大肠杆菌如何降解饮食NHYDRO-N-乙酰尿酸。我们最近的结果表明，可能涉及激酶和以太酶。因此，我们目前的努力旨在净化这些活动，以确定负责活动的基因。目标＃3：确定β-内酰胺酶的真正诱导剂。 AIM＃4：确定抗原43的表达与Murein三肽的回收如何有关。抗原43引起自身凝集，促进生物膜形成。 Deletion of either murein peptide ligase (mpl) or murein peptide amidase A (mpaA) results in production of tripeptide and antigen 43 suggesting that accumulation of the murein tripeptide, L-Ala-gamma-D-Glu-meso-diaminopimelic acid, may be involved.