Characterization of gene cluster for glycophosphoinositides of mycobacteria

分枝杆菌糖磷酸肌醇基因簇的表征

• 批准号: 7835665
• 负责人: Mary Jackson
• 金额: $ 7.35万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-08 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7835665
• 关键词: Actinobacteria class; Actinomyces; Acyltransferase; Address; Anabolism; Antimycobacterial Agents; Antitubercular Agents; Bacillus (bacterium); Bacterial Physiology; Biochemical; Biochemistry; Biogenesis; Bioinformatics; Biological Assay; Biological Process; Cell Wall; Cell membrane; Cells; Chromatography; Complex; Computer Simulation; Corynebacterium; Development; Dissection; Enzymes; Escherichia coli; Event; Gene Cluster; Gene Components; Genes; Genetic; Genome; Genus Mycobacterium; Goals; Immune response; Integral Membrane Protein; Knowledge; Laboratories; Lead; Lipopolysaccharides; Locales; Mannose; Mannosyltransferases; Membrane; Multi-Drug Resistance; Multienzyme Complexes; Mycobacterium Infections; Mycobacterium tuberculosis; Nature; Nocardia; Open Reading Frames; Paratuberculosis; Pathogenesis; Pathogenicity; Pathway interactions; Phosphatidylinositols; Physiology; Play; Proteins; Recombinants; Role; Side; Structure; Techniques; Therapeutic Agents; Therapeutic Intervention; Tuberculosis; Validation; Work; analytical tool; base; enzyme pathway; genetic analysis; glycosyltransferase; homologous recombination; lipoarabinomannan; lipomannan; mutant; mycobacterial; novel; novel therapeutics; overexpression; periplasm; phosphatidylinositol mannoside; public health relevance; resistant strain; sugar; tuberculosis drugs

DESCRIPTION (provided by applicant): The emergence of multi-drug resistant (MDR) strains of Mycobacterium tuberculosis has led to a critical need for new therapeutic agents against tuberculosis. M. tuberculosis is endowed with a diverse range of glycosylphosphatidylinositides such as phosphatidylinositol mannosides (PIMs), lipomannan (LM) and lipoarabinomannan (LAM), which play an important role in the physiology as well as the immunopathogenesis of mycobacterial infection. Enormous progress has been made in delineating the structure and biosynthesis of PIMs, but until recently the enzymes and steps leading to LM/LAM biosynthesis were not known. The elucidation of the catalytic steps involved in the synthesis of these molecules will help define one of the most complex biosynthetic pathways of mycobacteria in addition to providing new targets for the identification of novel anti-mycobacterial agents. Mutants defective in their synthesis should also enable a precise contribution of these molecules to the immunopathogenesis of tuberculosis. We have recently identified two genes encoding mannosyltransferases responsible for the terminal steps of LM/LAM biosynthesis. In silico analysis of the genetic locale of these genes revealed a possible PIM/LM/LAM biosynthetic gene cluster in the genome of M. tuberculosis. In order to define the PIM/LM/LAM biosynthetic pathways of mycobacteria, we have begun the characterization of genes from this cluster. Thus, the specific aims of this proposal are: 1. Characterization of an acyltransferase by genetic and biochemical approaches; 2. Functional characterization of a protein potentially involved in the transport of PIMs across the plasma membrane. PUBLIC HEALTH RELEVANCE: Identification and characterization of a gene cluster for glycosylphosphatidylinositides of mycobacteria. Dissection of the glycosylphosphatidylinositide (GPI) pathway in mycobacteria will lead to the discovery of a novel class of essential enzymes of M. tuberculosis that may represent new targets for therapeutic intervention. In addition, the mutants defective in some aspects of GPI synthesis will help define the precise role of these molecules in immunopathogenesis.

描述（由申请人提供）：结核分枝杆菌多重耐药（MDR）菌株的出现导致对新的结核病治疗剂的迫切需求。结核分枝杆菌富含多种糖基磷脂酰肌醇，例如磷脂酰肌醇甘露糖苷（PIM）、脂甘露聚糖（LM）和脂阿拉伯甘露聚糖（LAM），它们在分枝杆菌感染的生理学和免疫发病机制中发挥重要作用。在描述 PIM 的结构和生物合成方面已经取得了巨大进展，但直到最近，导致 LM/LAM 生物合成的酶和步骤仍然未知。阐明这些分子合成中涉及的催化步骤将有助于定义分枝杆菌最复杂的生物合成途径之一，此外还为鉴定新型抗分枝杆菌药物提供新靶点。合成缺陷的突变体也应该能够使这些分子对结核病的免疫发病机制做出精确的贡献。我们最近鉴定了两个编码甘露糖基转移酶的基因，负责 LM/LAM 生物合成的最终步骤。对这些基因的遗传区域的计算机分析揭示了结核分枝杆菌基因组中可能存在 PIM/LM/LAM 生物合成基因簇。为了定义分枝杆菌的 PIM/LM/LAM 生物合成途径，我们已经开始对该簇的基因进行表征。因此，本提案的具体目标是： 1. 通过遗传和生化方法表征酰基转移酶； 2. 可能参与 PIM 跨质膜运输的蛋白质的功能表征。公共卫生相关性：分枝杆菌糖基磷脂酰肌醇基因簇的鉴定和表征。对分枝杆菌中糖基磷脂酰肌醇（GPI）途径的剖析将导致发现结核分枝杆菌的一类新型必需酶，这可能代表治疗干预的新靶标。此外，GPI 合成某些方面存在缺陷的突变体将有助于确定这些分子在免疫发病机制中的精确作用。