Origin of mitochondrial proton leak: comparative investigation of Adenine Nucleotide, Translocase, Phosphate and Aspartat/Glutamate Carriers

线粒体质子泄漏的起源：腺嘌呤核苷酸、易位酶、磷酸盐和天冬氨酸/谷氨酸载体的比较研究

• 批准号: 40116377
• 负责人: Professorin Dr. Elena E. Pohl
• 金额: --
• 依托单位: Institut für Physiologie, Pathophysiologie und Biophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/40116377?language=en
• 关键词: Origin; mitochondrial; proton; leak; comparative

During oxidative phosphorylation protons are driven back into the matrix through the F1/F0-ATP synthase or return through alternative pathways (leak), lowering the efficiency of ATP synthesis. Origin and significance of the proton leak is not well understood. If catalyzed by members of uncoupling protein subfamily it results in nonshivering thermogenesis in brown adipose tissue (UCP1) or it may participate in the regulation of reactive oxygene species in other tissues (UCP2-UCP5). Experiments on isolated mitochondria indicate that also other mitochondrial carriers may significantly contribute to H+ leak. The latter will be investigated in the present project using model membranes reconstituted with highly purified proteins: adenine nucleotide translocase (ANT), phosphate (PIC) or (iii) aspartate/glutamate carriers (AGC). The modulating role of membrane lipid composition, transmembrane and dipole potentials will be studied. The necessity of the fatty acid binding to proteins will be proved by site-directed mutagenesis. Comparing the single molecule proton conductances of ANT, PIC, AGC and uncoupling proteins, their relative contributions to basal and inhibitor-sensitive membrane proton leaks will be evaluated.

在氧化磷酸化过程中，质子通过F1/F0-ATP合酶或通过替代途径（泄漏）返回基质，降低ATP合成的效率。质子泄漏的起源和意义还不清楚。如果由解偶联蛋白亚家族成员催化，则导致棕色脂肪组织中的非颤抖性产热（UCP 1），或者可能参与其他组织中的活性氧种类的调节（UCP 2-UCP 5）。对分离的线粒体的实验表明，其他线粒体载体也可能显着有助于H+泄漏。后者将在本项目中使用高度纯化的蛋白质重组模型膜进行研究：腺嘌呤核苷酸转位酶（ANT），磷酸盐（PIC）或（iii）天冬氨酸/谷氨酸载体（AGC）。将研究膜脂质组成、跨膜电位和偶极电位的调节作用。脂肪酸与蛋白质结合的必要性将通过定点突变来证明。比较ANT、PIC、AGC和解偶联蛋白的单分子质子电导，将评估它们对基底和通道敏感膜质子泄漏的相对贡献。