PROTON TRANSLOCATION THROUGH F1F0 ATP SYNTHASE

改变线粒体DNA的突变与衰老和 退行性疾病，以及特定的遗传性疾病。一些人 患有这些疾病的患者有ATPase-6亚单位基因的突变 F1F0三磷酸腺苷合成酶。检测到ATPase-6-leu156-Arg突变 四个不相关的疾病患者家属被诊断为 利综合征(NARP)。两者之间的严重程度有关联 症状、发病年龄和线粒体缺陷百分比 基因组。我们通过以下方式对疾病突变的理解做出了贡献 在大肠杆菌F1F0三磷酸腺苷合成酶中建模，并测定 这种酶功能的丧失是由于质子(H+)的缺陷 易位。线粒体突变对衰老的影响更大 脆弱的。然而，大量影响a基因的错义突变 亚基导致大肠杆菌中F1F0ATP合成酶的丢失。相似点 毫无疑问，人类ATPase-6基因会发生突变，导致丢失 氧化磷酸化，而且大多数仍将在 临床环境。 我们的长期目标是了解 质子(H~+)转运及其与H~+转运的耦合 F1F0三磷酸腺苷合成酶的催化作用。实验室 致力于使用突变方法来研究结构 和F0亚基的功能。本提案的核心是使用 研究F0内分子相互作用的分子生物学方法。 我们建议进行涉及第二位点抑制子生成的研究。 突变，深入研究F0突变对F1的影响 调查b亚基中可能涉及 H+转位与催化的耦合及新途径 考虑亚基之间的分子相互作用 将F1扇区连接到F0扇区。

Mutations altering mitochondrial DNA have been linked to aging and degenerative diseases, as well as, to specific inherited disorders. Some patients with these disorders have mutations in the ATPase-6 subunit gene of F1F0 ATP synthase. The ATPase-6-leu156-arg mutation was detected in four unrelated families of patients with diseases variously diagnosed as Leigh Syndrome (NARP). A correlation was drawn between severity of symptoms, age of onset and the percentage of defective mitochondrial genomes. We contributed to the understanding of the disease mutation by modeling it in the Escherichia coli F1F0 ATP synthase, and determining that enzyme function was lost due to a defect in proton (H+) translocation. The effects of mitochondrial mutations on aging is more tenuous. However, a large number of missense mutations affecting the a subunit result in a loss of F1F0 ATP synthase in E. coli. Similar point mutations undoubtedly occur in the human ATPase-6 gene resulting in loss of oxidative phosphorylation, and most will remain undetected in the clinical setting. Our long-term goal is to gain an understanding of the mechanisms of proton (H+) translocation and the coupling of H+ translocation to catalysis in F1F0 adenosine triphosphate (ATP) synthase. The laboratory is committed to using a mutagenesis approach for investigating structure and function of the F0 subunits. The present proposal centers on using the molecular biology approach to study molecular interactions within F0. We propose studies involving the generation of second-site suppressor mutations, study of the effects of F0 mutations on F1, in depth investigation of a site in the b subunit likely to be involved in the coupling of H+ translocation to catalysis, and to take a novel approach for considering the molecular interactions between the subunits connecting the F1 sector to the F0 sector.