Molecular Studies Of Protein-dna Interactions

我们试图在分子水平上理解生物体在适应遗传多样性需要的同时保持其基因组完整性的各种方法。我们的研究工作目前集中在DNA修复的关键途径，DNA错配修复。错配修复以大肠杆菌甲基导向错配修复途径为例，其目标是通过DNA复制错误、同源重组和自发DNA损伤引起的碱基对错配。由mutS和mutL基因编码的错配修复系统的组成部分在整个进化过程中高度保守，错配修复的失活导致自发突变率的大幅增加。人类错配修复酶的缺陷与散发性和遗传性癌症有关。在先前工作的基础上，mts - adp错配复合物的晶体结构揭示了复合atp酶活性位点的关键残基和核苷酸结合引起的构象变化。生化实验提供了错配修复的关键中间体的证据，该中间体涉及与DNA错配结合的MutS和MutL复合物。这种复合物的形成是在修复过程中下游事件的信号，需要ATP。

We seek to understand at a molecular level the various ways by which an organism maintains the integrity of its genome while accommodating the need for genetic diversity. Our research efforts currently focus on a key DNA repair pathway, DNA mismatch repair. Mismatch repair, exemplified by the E. coli methyl-directed mismatch repair pathway, targets base pair mismatches that arise through DNA replication errors, homologous recombination and spontaneous DNA damage. Components of the mismatch repair system encoded by the mutS and mutL genes are highly conserved throughout evolution, and inactivation of mismatch repair results in a large increase in the rate of spontaneous mutation. Defects in human mismatch repair enzymes have been implicated in sporadic and hereditary cancers. Building on previous work, the crystal structure of a MutS-ADP-mismatch complex reveals key residues in the composite ATPase active site and conformational changes induced by nucleotide binding. Biochemical experiments provide evidence for a key intermediate in mismatch repair involving a complex of MutS and MutL bound to a DNA mismatch. Formation of this complex that signals downstream events in repair requires ATP.