牛心线粒体ATP酶抑制蛋白对酶的催化部位构象的影响

Regulatory Function of Mitochondrial ATPase Inhibitor Protein on Catalytic Portion of ATPase

以标记在ＡＴＰ酶（Ｆ_１）催化部位的ＴＮＰ－ＡＴＰ为荧光探针，比较测定了Ｆ_１与其抑制蛋白（ＩＦ_１）结合前后的ＴＮＰ－ＡＴＰ荧光光谱、荧光寿命和荧光偏振光谱。结果表明在ＩＦ１的作用下，酶分子催化部位的极性下降，ＴＮＰ－ＡＴＰ分子运动的自由度减小，提示ＩＦ_１引起了Ｆ_１催化部位的构象改变。

The regulatory function of mitochondrial ATPase inhibitor (IF1) on catalytic portion of ATPase (F1) was investigated by using labelled F1 with fluorescent ATP derivatve 2’, 3’,-0(2, 4, 6-trinitrocyclohexadienylidene) adenosine 5’-triphosphate (TNP-ATP).The fluorescent parameters including fluorescent spectra, fluorescent lifetime and polarization spectra were determined for TNP-ATP-F1 and IF1-TNP-ATP-F1. These data indicate that IF1 significantly alters the polarity of the catalytic portion of F1 and the catalytic portion became more constricted under the action of IF1.