MOLECULAR MECHANISM OF REDOX REGULATION OF CHLOROPLAST ATP SYNTHSAE

在本项目中，我们打算在分子水平上了解叶绿体ATP合成酶的氧化还原调节。在这三年的研究中，我们获得了以下几个重要的发现：A.将氧化还原敏感型叶绿体F1的γ亚基的切换区导入细菌F1，揭示了旋转的氧化还原切换。我们发现，氧化F1的酶活性受到抑制的特征是旋转行为中更频繁的长时间停顿。B.利用膜整合嵌合复合体研究了叶绿体三磷酸腺苷合成酶γ和ε亚基的调节功能。我们的结论是，这些亚基之间的相互作用对于γ亚基对FoF1复合体的氧化还原调节是重要的，并且这些调节亚基与酶的催化核心之间必须有一定的结构匹配才能赋予细菌FoF1C氧化还原调节机制。基于三维结构分析，细菌F1对胞质外膜F1的特异性抑制肽--天冬氨酸的敏感性是通过单一氨基酸取代而获得的。然后研究了突变体F1在该抑制剂存在下的旋转性。揭示了该抑制剂引起的停顿的变化。

In this project, we intended to understand the redox regulation of chloroplast ATP synthase at the molecular level. For these three research years, we obtained the several important findings as follows:A.The switch region from the γ subunit of the redox-sensitive chloroplast F1 was introduced into the bacterial F1 and the redox switching of the rotation was revealed. We revealed that the suppressed enzymatic activity of the oxidized Fl was characterized by more frequent long pauses in the rotation behaviour.B.The regulatory function of the γ and ε subunits of chloroplast ATP synthase was studied using the membrane integrated chimeric complex. We concluded that the interaction between these subunits is important for the redox regulation of FoF1 complex by the γ subunit, and a certain structural matching between these regulatory subunits and the catalytic core of the enzyme must be required to confer the redox regulation mechanism to the bacterial FoF1.C.The sensitivity against tentoxin, the specific inhibitor peptide for the chioroplast F1, was conferred to the bacteria Fl by a single amino acid substitution based on the three dimensional structure analysis. Then the rotation of this mutant Fl was investigated in the presence of this inhibitor. The change of the pauses induced by the inhibitor was revealed.