镁离子介导的脂质流动性变化增强了重组氢-ATP酶活性。

Mg2+-mediated change in lipid fluidity enhances the reconstituted H+-ATPase activity.

作者信息

Yang F Y, Guo B Q, Wang D H

出版信息

Sci Sin B. 1983 Oct;26(10):1046-56.

Abstract

The results by using ANS fluorescent probe and spin labels 5-NS show that the fluidity of L. (H+-ATPase) +Mg2+ (H+-ATPase from pig heart mitochondria reconstituted in the presence of Mg2+) is less than that of L. (H+-ATPase) -Mg2+ (proteoliposome reconstituted in the absence of Mg2+). But no significant difference in fluidity has been observed when both reconstituted systems were monitored by using spin labels 12-NS and 16-NS. This indicates that Mg2+ may cause changes in fluidity of the lipid molecules near the surfaces of the bilayers, but does not affect significantly the fluidity of the deeper layer of the reconstituted system. It is tentatively supposed that in the presence of Mg2+, enhancement of activities of reconstituted H+-ATPase may be due to the Mg2+-mediated change in physical state of the lipids in the more superficial region of lipid bilayers so as to ensure a suitable conformation of ATPase complex, thereby possessing higher activity.

摘要

使用ANS荧光探针和自旋标记物5-NS的结果表明，L.（H⁺-ATP酶）+Mg²⁺（在Mg²⁺存在下重构的猪心线粒体H⁺-ATP酶）的流动性小于L.（H⁺-ATP酶）-Mg²⁺（在无Mg²⁺情况下重构的蛋白脂质体）的流动性。但是，当使用自旋标记物12-NS和16-NS监测这两种重构体系时，未观察到流动性有显著差异。这表明Mg²⁺可能会导致双层膜表面附近脂质分子的流动性发生变化，但对重构体系较深层的流动性没有显著影响。初步推测，在Mg²⁺存在的情况下，重构的H⁺-ATP酶活性增强可能是由于Mg²⁺介导了脂质双层较表层区域脂质物理状态的变化，从而确保了ATP酶复合体具有合适的构象，进而具有更高的活性。