Structural biology of human DNA mismatch repair machinery

人类DNA错配修复机制的结构生物学

• 批准号: 7937767
• 负责人: LORENA S. BEESE
• 金额: $ 32.37万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7937767
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; ATPase Domain; Address; Apoptosis; Apoptotic; Atlas of Cancer Mortality in the United States; Attention; Base Sequence; Binding; Binding Sites; Biochemical; Biological Assay; Cisplatin; Collaborations; Complex; Computer Simulation; Coupling; DNA; DNA Binding Domain; DNA Damage; DNA lesion; Defect; Development; Disease; Drug effect disorder; Ensure; Escherichia coli; Excision; Exodeoxyribonuclease I; Fragile X Syndrome; Gap Junctions; Generations; Genes; Genetic Recombination; Genome; Genome Stability; Genomic Instability; Goals; Hand; Health; Hereditary Nonpolyposis Colorectal Neoplasms; Heteroduplex DNA; Homologous Gene; Homology Modeling; Human; Huntington Disease; Hydrolysis; Immunoglobulin Somatic Hypermutation; In Vitro; Inherited; Investigation; Lesion; Letters; Life; Link; MSH2 gene; MSH3 gene; MSH6 gene; Malignant Neoplasms; Maps; Mediating; Mismatch Repair; Molecular; Mutagenesis; Mutation; Myotonic Dystrophy; N-terminal; Nucleotides; Pathogenesis; Pathway interactions; Pharmaceutical Preparations; Play; Predisposition; Process; Proliferating Cell Nuclear Antigen; Proteins; Roentgen Rays; Role; Sequence Alignment; Series; Signal Transduction; Solutions; Specificity; State Interests; Structural Biochemistry; Structure; Substrate Specificity; Syndrome; System; Testing; Therapeutic; Trinucleotide Repeats; Turcot Syndrome; X-Ray Crystallography; Yeasts; adduct; base; chemotherapeutic agent; conformational conversion; design; endonuclease; human DNA; human disease; in vivo; insertion/deletion mutation; insight; link protein; mutant; nucleotide analog; reconstitution; repaired; response; structural biology; tumor

DNA mismatch repair (MMR) is a major contributor to genome stability. MMR corrects DNA biosynthetic errors, ensures the fidelity of genetic recombination and is required for the cellular response to certain classes of DNA damage, including lesions induced by several chemotherapeutic drugs (e.g. cisplatin). MMR also has an essential role in somatic hypermutation for the generation of immunoglobin diversity. Defects in human MMR are associated with a strong predisposition to tumor development, and mutagenic expansion of CTG-CAG repeat sequence which are the causative mutations for several meuromuscular diseases (Huntington's disease, fragile-X syndrome, and myotonic dystrophy). Despite the importance of this system in human health and disease, our understanding of its molecular mechanisms is limited. We propose to combine X-ray crystallography, solution small angle X-ray scattering (SAXS) and biochemical approaches to study the human protein-DNA assemblies that are key intermediates in the lesion recognition and excision steps of MMR. We are fortunate that the human MMR pathway has now reached the maturity of analysis that obtaining the protein components and their crystals is now in hand and can be studied directly. We have already determined crystal structures of human MutS¿ DNA lesion recognition complexes. In Aim 1 we propose to determine crystal structures of Exo1 and MutS¿. In Aim 2 we investigate substrate recognition, specificity and ATP-dependent conformational transitions of MMR components. In Aim 3 we study two key multi-component assemblies essential to the recognition and excision process. Together the aims will contribute to furthering our understanding of the molecular basis of MMR-associated human diseases.

DNA错配修复（MMR）是基因组稳定性的主要贡献者。MMR纠正DNA 生物合成错误，确保遗传重组的保真度，是细胞 对某些类型的DNA损伤的反应，包括由几种 化疗药物（例如顺铂）。MMR在体细胞超突变中也有重要作用 产生免疫球蛋白多样性。人类MMR的缺陷与 对肿瘤发展有强烈的易感性，CTG-CAG重复序列的突变性扩增 序列，其是几种神经肌肉疾病（亨廷顿氏病）的致病突变 疾病、脆性X综合征和强直性肌营养不良）。尽管该系统在 人类健康和疾病，我们对其分子机制的了解是有限的。我们提出 将联合收割机X射线晶体学、溶液小角X射线散射（SAXS）和生物化学 研究人类蛋白质-DNA组装体的方法，这些组装体是病变中的关键中间体 MMR的识别和切除步骤。我们很幸运，人类MMR通路现在 分析技术已经成熟，获得蛋白质组分及其晶体的方法已经成熟， 手，可以直接研究。我们已经确定了人类MutS的晶体结构。 DNA损伤识别复合物。在目标1中，我们提出确定Exo 1的晶体结构 和MutS。在目标2中，我们研究了底物识别，特异性和ATP依赖性 MMR组分的构象转变。在目标3中，我们研究了两个关键的多分量 这些集会对承认和切割过程至关重要。这些目标将有助于 促进我们对MMR相关人类疾病的分子基础的理解。