AceK作为高效的ATP水解酶其机理及功能转换的理论研究
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- 英文论文题名：Theoretical studies of function switch and mechanism of AceK as a highly active ATPase
- 论文作者：秦佳佳 ; 谭宏伟 ; 陈光巨 ; 郑积敏 ; 贾宗超
- 英文论文作者：Jiajia Qin ; Hongwei Tan ; Guangju Chen ; Jimin Zheng ; Zongchao Jia ; College of Chemistry ; Beijing Normal University
- 年：2016
- 作者机构：北京师范大学化学学院;
- 论文关键词：异柠檬酸脱氢酶激酶/磷酸酶 ; 密度泛函理论 ; ATP水解反应机理 ; 功能转换
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第四十五分会：物理有机
- 语种：中文
- 分类号：Q55
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第四十五分会 ; 物理有机
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：213k
- 原文格式：D
- 会议级别：全国
摘要
异柠檬酸脱氢酶激酶/磷酸酶(AceK)是大肠杆菌在低营养环境下代谢调控的关键酶,通过对底物异柠檬酸(ICDH)进行磷酸化或去磷酸化从而调节和控制大肠杆菌的代谢旁路。AceK作为多功能蛋白酶,在同一活性中心既具有激酶、磷酸酶活性,又具有ATP水解酶活性~([1,2])。同激酶、磷酸酶活性相比,AceK呈现极其高的ATP水解酶活性~([2]),其高ATP水解酶活性的原因以及生理作用尚未明确。实验表明,底物对AceK的ATP水解酶活性具有部分抑制作用~([3]),其抑制原因也是未知的。本课题,使用密度泛函理论方法,对AceK的ATP水解反应机理进行研究,并证实了ATP水解反应遵循解离型反应机理且其活化能仅为17.85 kcal·mol~(-1),在理论上支持了AceK的高ATP水解酶活性。AceK高ATP水解酶活性可能为完成磷酸酶反应提供接受质子的ADP。基于理论计算和结构分析,AceK与底物结合引起了活性中心残基Asp477的翻转,从而局部抑制了其ATP水解酶的活性,有利于其激酶和磷酸酶反应的进行。本课题在理论上阐明了AceK的ATP水解反应机理及其功能转换。
As a multi-function enzyme, AceK integrates kinase, phosphatase and ATPase activities in the single active site. AceK exhibits unusually high ATPase activity comparing to its kinase and phosphatase activities. How AceK possesses such a high ATPase activity and what governs function regulation are still elusive. In this work, we have employed DFT methods to exploit ATP hydrolysis mechanism of AceK and revealed a dissociative pathway with activation energy of only 17.85 kcal·mol~(-1). The high ATPase activity of AceK may play a role to produce ADP as the proton acceptor to fulfill its phosphatase function. Based on our calculations and structural analyses, binding with substrate ICDH causes a catalytically important residue, Asp477, to flip over and further suppresses AceK ATPase activity, thus favoring kinase or phosphatase activities.
As a multi-function enzyme, AceK integrates kinase, phosphatase and ATPase activities in the single active site. AceK exhibits unusually high ATPase activity comparing to its kinase and phosphatase activities. How AceK possesses such a high ATPase activity and what governs function regulation are still elusive. In this work, we have employed DFT methods to exploit ATP hydrolysis mechanism of AceK and revealed a dissociative pathway with activation energy of only 17.85 kcal·mol~(-1). The high ATPase activity of AceK may play a role to produce ADP as the proton acceptor to fulfill its phosphatase function. Based on our calculations and structural analyses, binding with substrate ICDH causes a catalytically important residue, Asp477, to flip over and further suppresses AceK ATPase activity, thus favoring kinase or phosphatase activities.
引文
[1]Stueland,C.S.;Ikeda,T.P.;La Porte,D.C.J.Biol.Chem.1989,264(23):13775.
[2]Zheng,J.;Jia,Z.Nature.2010,465(7300):961.
[3]Stueland,C.S.;Eck,K.R.;Stieglbauer,K.T.;La Porte,D.J.Biol.Chem.1987,262(33):16095.
[2]Zheng,J.;Jia,Z.Nature.2010,465(7300):961.
[3]Stueland,C.S.;Eck,K.R.;Stieglbauer,K.T.;La Porte,D.J.Biol.Chem.1987,262(33):16095.