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(申请人提供)：由于缺乏有效的化疗药物和抗药性菌株的发展，结核病再次成为一个公共卫生问题变得更加复杂。结核分枝杆菌的细胞壁是一些最有效的抗分枝杆菌药物的靶标，包括乙胺丁醇，已知的是抑制细胞壁阿拉伯半乳糖(AG)和相关的脂阿拉伯甘露聚糖(LAM)的生物合成。过去几年的各种生物学研究共同提供了令人信服的证据，表明LAM是宿主与病原体相互作用的关键表面分子。由于耐药性和基因操作的结果，截短的、突变的LAM变异体的出现为旨在确定LAM在发病机制中的相关性的结构和功能研究提供了宝贵的模型化合物。具体地说，将表征阿拉伯糖组装及其与磷脂酰肌醇甘露聚糖核心的附着点(S)的精细细节，并将确定与临床分离株的特定生物学属性正相关的结构细节。将确定LAM微观异质性的结构基础，并从LAM衍生出化学和/或酶修饰的阿拉伯聚糖和甘露聚糖，用于结构/生物学研究。作为一个重要的副产品，最近由于embCAB蛋白的遗传操作而产生的细胞壁突变体的出现，以及对基因产物的分析，现在使我们能够理性地剖析LAM/AG的阿拉伯聚糖的形成途径。同样，对结核分枝杆菌LAM突变体的研究，以及我们在产生LAM缺乏型结核分枝杆菌方面的共同努力，将直接有助于解决LAM在生物生存/传染性方面的作用。因此，这项研究建议的统一主题包括LAM的结构分析和操纵，辅之以遗传探针以改变其结构和突变耻垢分枝杆菌和结核分枝杆菌的LAM，所有这些都与生物学和生物合成有关。