Targets in Mycobacterium Tuberculosis: Stress Resistance & Repair

结核分枝杆菌的目标：抗应激性

• 批准号: 7385159
• 负责人: CARL Francis NATHAN
• 金额: $ 86.15万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7385159
• 关键词: 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one; AIDS/HIV problem; Abbreviations; Acetyl Coenzyme A; Alcohols; Alleles; Amino Acids; Anabolism; Antibiotics; Antioxidants; Attenuated; Back; Bacterial Infections; Biological Assay; Bioterrorism; Calmette-Guerin Bacillus; Carboxy-Lyases; Catabolism; Cause of Death; Cell Wall; Cells; Chemicals; Citric Acid; Citric Acid Cycle; Coenzyme A; Complement; Complex; Condition; Cultured Cells; DNA; DNA Damage; DNA Repair; DNA Repair Enzymes; Disease; Disruption; Dithionitrobenzoic Acid; Drug Kinetics; Drug Resistant Tuberculosis; Drug resistance; Economics; Electrons; Enzymes; Equilibrium; Fatty Acids; Figs - dietary; Folate; Fright; Gene Expression Microarray Analysis; Gene Targeting; Generations; Genes; Grant; Growth; HIV Infections; Harvest; Health; Heme; Homologous Gene; Human; Human Genome; Hydrogen Peroxide; Immune; Immune response; Immunity; In Vitro; Incidence; Infection; Inhibitory Concentration 50; Interferons; Intermediate resistance; Keto Acids; Kinetics; Libraries; Limb structure; Lipids; Mediating; Metabolic; Metabolism; Methodology; Multi-Drug Resistance; Multidrug-Resistant Tuberculosis; Mus; Mutagenesis; Mutation; Mycobacterium tuberculosis; NADH; NOS2A gene; New Agents; Nitrites; Nitrogen; Nucleic Acids; Nucleotide Excision Repair; Numbers; Operative Surgical Procedures; Operon; Oxidases; Oxidoreductase; Pathway interactions; Peroxidase; Peroxidases; Peroxides; Peroxonitrite; Phagocytes; Phagosomes; Pharmaceutical Preparations; Phenotype; Physiological; Polymerase Chain Reaction; Production; Proteins; Range; Reporting; Research Personnel; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Safety; Solutions; Specificity; Staging; Stress; Structure; Structure-Activity Relationship; Succinate-semialdehyde dehydrogenase; Succinates; System; Testing; Thiamine Pyrophosphate; Time; Tuberculosis; Ultraviolet Rays; Water; Work; X-Ray Crystallography; acetoacetyl CoA; alkyl hydroperoxide reductase; bactericide; base; chemical genetics; chemotherapy; combinatorial; dihydrolipoamide acyltransferase; dihydrolipoamide dehydrogenase; dihydrolipoamide succinyltransferase; drug development; high throughput screening; homologous recombination; human NOS2A protein; inhibitor/antagonist; isoniazid; ketoglutarate dehydrogenase; killings; lipoamide; macrophage; man; mecarzole; mutant; novel; pathogen; peroxynitrite reductase; propionyl-coenzyme A; pyruvate dehydrogenase; reactive oxygen intermediate; repaired; small molecule libraries; succinate; succinic semialdehyde; thioredoxin reductase; ultraviolet

DESCRIPTION (provided by applicant): M. tuberculosis (Mtb), a global health crisis and bioterrorism threat, is increasingly drug-resistant, but little new chemotherapy has emerged in decades. A fresh approach to chemotherapy is to target pathways essential for the pathogen to survive in its metabolic niche in host macrophages. This application is based on the hypothesis that Mtb requires 3 enzymes to survive under energy-poor, oxidative and nitrosative conditions in the phagosome: (1) Lipoamide dehydrogenase (Lpd) serves in pyruvate dehydrogenase and probably in branched chain ketoacid dehydrogenase as well as in peroxynitrite reductase /peroxidase and thus is key for net synthesis of acyl CoA's, the precursors of fatty acids, and for resistance to reactive nitrogen intermediates (RNI). (2) a-ketoglutarate (KG) decarboxylase (KDC) converts KG to succinic semialdehyde (SSA), replacing KG dehydrogenase, which Mtb lacks. SSA dehydrogenase converts SSA to succinate and may thereby connect the oxidative and reductive limbs of Mtb's citric acid cycle (CAC). KDC may therefore be important for Mtb's generation of energy, reducing equivalents, amino acids and heme. (3) Ultraviolet repair (Uvr) B, part of the nucleotide excision repair pathway, was found by saturation transposon mutagenesis to be essential for Mtb to survive RNI and to kill mice. KDC and UvrB lack human homologs, and Lpd's crystal structure shows key differences from the human enzyme. We will use allelic replacement to disrupt the 3 genes encoding these enzymes, or establish their essentiality; use conventional and novel combinatorial libraries to identify chemical inhibitors of each enzyme; analyze the crystal structures of Lpd and KDC with and without inhibitors; and assess these enzymes as potential targets for new chemotherapeutics. Antibiotics to date only target enzymes that synthesize protein, nucleic acids, cell walls and folate. The fundamental novelty of this work is to broaden the range of targets to include enzymes of intermediary metabolism and DNA repair.

描述(申请人提供)：结核分枝杆菌(结核分枝杆菌)，一个全球性的健康危机和生物恐怖主义威胁，越来越多的抗药性，但几十年来几乎没有新的化疗出现。一种新的化疗方法是靶向病原体在宿主巨噬细胞的代谢生态位中生存所必需的途径。这一应用是基于这样的假设，即Mtb需要3种酶才能在吞噬体内的低能量、氧化和亚硝化条件下生存：(1)脂酰胺脱氢酶(LPD)服务于丙酮酸脱氢酶，可能服务于支链酮酸脱氢酶以及过氧亚硝酸盐还原酶/过氧化物酶，因此对于脂肪酸前体酰辅酶A的净合成和对活性氮中间体(RNI)的抗性是关键。(2)α-酮戊二酸(KG)脱羧酶(KDC)能将KG转化为琥珀酸半醛(SSA)，取代Mtb所缺乏的KG脱氢酶。SSA脱氢酶将SSA转化为琥珀酸，从而可能连接结核分枝杆菌柠檬酸循环(CAC)的氧化和还原分支。因此，KDC可能对结核分枝杆菌的能量生成很重要，减少了当量、氨基酸和血红素。(3)紫外线修复(UVR)B是核苷酸切除修复途径的一部分，通过饱和转座子诱变发现，UVR B是Mtb在RNI中存活和杀死小鼠所必需的。KDC和UvrB缺乏人类同源物，LPD的晶体结构显示出与人类酶的关键差异。我们将使用等位基因置换来扰乱编码这些酶的3个基因，或确定它们的重要性；使用传统的和新型的组合文库来确定每个酶的化学抑制剂；分析LPD和KDC的晶体结构，并评估这些酶作为新的化疗药物的潜在靶点。到目前为止，抗生素只针对合成蛋白质、核酸、细胞壁和叶酸的酶。这项工作的基本新颖性是扩大了靶标的范围，将中间代谢和DNA修复的酶包括在内。