pH依赖性构象变化调节线粒体ATP酶抑制蛋白的功能活性。

pH dependent conformational changes modulate functional activity of the mitochondrial ATPase inhibitor protein.

作者信息

Sah J F, Kumar C, Mohanty P

机构信息

Bioenergetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.

出版信息

Biochem Biophys Res Commun. 1993 Aug 16;194(3):1521-8. doi: 10.1006/bbrc.1993.1997.

DOI:10.1006/bbrc.1993.1997

PMID:8352810

Abstract

A 12kDa, heat stable protein (IF1) inhibiting hydrolytic activity of submitochondrial particles was purified to electrophoretic homogeneity from buffalo heart mitochondria. Specific activity of the purified fraction was > 5000 units/mg. Maximal inhibition was observed at pH 6.0 and was Mg++ and ATP dependent. Circular dichroism studies showed that the inhibitor peptide undergoes a dramatic, reversible conformational change in response to pH which correlates well with its ability to inhibit ATP hydrolysis catalyzed by inhibitor depleted submitochondrial particles. It is shown for the first time that IF1 with a predominantly beta-sheet component is more efficient at suppressing ATPase activity.

摘要

从水牛心脏线粒体中纯化出一种12kDa的热稳定蛋白（IF1），该蛋白可抑制亚线粒体颗粒的水解活性，纯化至电泳纯。纯化组分的比活性>5000单位/毫克。在pH 6.0时观察到最大抑制作用，且依赖于Mg++和ATP。圆二色性研究表明，该抑制肽会因pH值发生显著的、可逆的构象变化，这与其抑制抑制剂缺失的亚线粒体颗粒催化的ATP水解的能力密切相关。首次表明，主要由β-折叠组成的IF1在抑制ATP酶活性方面更有效。