Structure of LAM in Relation to Biology and Biosynthesis

LAM 结构与生物学和生物合成的关系

• 批准号: 6850695
• 负责人: DELPHI CHATTERJEE
• 金额: $ 25.38万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6850695
• 关键词: Mycobacterium tuberculosis; SDS polyacrylamide gel electrophoresis; T lymphocyte; bacterial antigens; carbohydrate receptor; carbohydrate structure; cell wall; cellular immunity; chemical structure function; drug resistance; galactans; macrophage; mannans; mass spectrometry; nuclear magnetic resonance spectroscopy; receptor sensitivity; site directed mutagenesis; surface antigens

DESCRIPTION (provided by applicant): The re-emergence of tuberculosis as a public health problem has been complicated by the lack of effective chemotherapeutic agents and the development of drug-resistant strains. The cell wall of the pathogen Mycobacterium tuberculosis, is known to be the target of some of the most effective anti-mycobacterial drugs including ethambutol which is known to inhibit the biosynthesis of the arabinan of cell wall arabinogalactan (AG) and the associated lipoarabinomannan (LAM). A diverse range of biological studies over the past few years has collectively provided compelling evidence implicating LAM as a key surface molecule in host-pathogen interactions. The availability of truncated, mutated LAM variants as a consequence of drug resistance and genetic manipulation provides invaluable model compounds for both structural and functional studies aiming at defining the relevance of LAM in pathogenesis. Specifically, the fine details of the arabinan assembly and its point(s) of attachment to the phosphatidylinositol mannan core will be characterized and structural niceties positively correlating with particular biological attributes of clinical isolates will be identified. Structural basis of microheterogeneity in LAM will be defined and chemically and/or enzymatically modified arabinan and mannan will be derived from LAM for structural/biological studies. As a major spin off, the recent availability of the consequential cell wall mutants due to genetic manipulation of the embCAB proteins, and analyses of the gene products now allows us rationally to dissect the pathway to the formation of the arabinan of LAM/AG. In the same vein, studies on LAM mutants in M. tuberculosis and our concerted efforts on generating LAM depleted M. tuberculosis will contribute directly into addressing the role of LAM in survival/infectivity of the organism. Thus, the unifying theme of this Research Proposal encompasses structural analysis and manipulation of LAM, supplemented by genetic probes to alter its structure and mutate LAM in M. smegmatis and M. tuberculosis all in relation to biology and biosynthesis.

描述（由申请人提供）：由于缺乏有效的化学治疗剂和耐药菌株的发展，结核病作为公共卫生问题的重新出现变得复杂。已知病原体分枝杆菌结核病的细胞壁是某些最有效的抗菌群药物的靶标，包括乙毛丁醇，已知可抑制Arabinanan的生物合成Arabinogalactan（AG）和相关的Lipoararabinomannan（LAM）。在过去的几年中，各种生物学研究范围都提供了令人信服的证据，暗示LAM是宿主 - 病原体相互作用中的关键表面分子。由于耐药性和遗传操纵而导致的截短，突变的LAM变体的可用性为结构和功能研究提供了宝贵的模型化合物，旨在定义LAM在发病机理中的相关性。具体而言，将表征阿拉伯集装的细节及其与磷脂酰肌醇曼南核心的附着点，并将确定与临床分离株的特定生物学属性成正相关的结构上的细节。 LAM中微观均匀性的结构基础将被定义，化学和/或酶修饰的阿拉伯人和Mannan将源自LAM进行结构/生物学研究。作为一个主要旋转，由于胚胎蛋白的基因操纵而导致的结果细胞壁突变体的最新可用性，以及对基因产物的分析，现在使我们能够理性地剖析LAM/AG的阿拉伯人形成的途径。同样，对结核分枝杆菌中的LAM突变体的研究以及我们在产生LAM的结核分枝杆菌的共同努力将直接有助于解决LAM在生物体的生存/感染中的作用。因此，该研究建议的统一主题涵盖了LAM的结构分析和操纵，并补充了遗传探针，以改变其结构和突变Smegmatis和M. tuberculcolisos中的LAM与生物学和生物合成有关。