大肠杆菌Nα-乙酰基转移酶RimI对人胸腺素α原N末端乙酰化修饰的影响

摘要

目的:研究大肠杆菌Nα-乙酰基转移酶RimI对人胸腺素α原(ProTα)N末端乙酰化修饰的影响.方法:在大肠杆菌中共表达ProTα与大肠杆菌Nα-乙酰基转移酶RimI,同时设置只表达ProTα的对照菌,分别提取纯化ProTα,利用HPLC检测其发生乙酰化修饰的程度.结果:ProTα的乙酰化修饰发生在翻译后水平,有无RimI的过表达、诱导时间的长短以及这两个因素之间的交叉效应均对ProTα的乙酰化程度有影响,其F值分别为53.8、89.22及16.28,P值均小于0.0001;无论有无RimI过表达,乙酰化的ProTα所占比例在诱导6 h后逐渐升高(P<0.0001);在过表达Ri-mI的菌株中,乙酰化的ProTα在诱导12 h后占37.4%,而在无RimI过表达的菌株中占64.3%;RimI对ProTα乙酰化的抑制作用从诱导6 h后开始显现(P=0.0007).结论:在大肠杆菌中,过量的Nα-乙酰基转移酶RimI可抑制人胸腺素α原的乙酰化修饰.%Objective: To investigate the effect of RimI, one of the Nα-terminal acetyltransferases of E.coli, on human prothymosin α(ProTα) acetylation.Methods: The human ProTα and Nα-terminal acetyltransferase RimI were co-expressed in E.coli DH5α.To observe the level of N-terminal acetylation on human ProTo, ProTα was purified and detected by HPLC.Results: The ProTα was post-translational acetylated.Over-expression of RimI, long term induction and the cross-effect could affect the level of N-terminal acetylation of ProTα(P＜0.0001).The increasing N-terminal acetylated ProTα could be observed after inducing 6 h, whether RimI was over-expressed or not (P＜0.0001).There were 37.4％ N-terminal acetylated ProTα in the presence of overdose RimI, 64.3％ N-terminal acetylated ProTα without of overdose RimI after inducing 12 h, and we could observe the inhibition after inducing 6 h(P=0.0007).Conclusion: The N-terminal acetylation of ProTα was inhibited when over-expressed Nα-terminal acetyltransferase RimI.