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采用DFT方法研究了烯酰基-辅酶A(ECH)催化的4-(N,N-二甲氨基)-肉桂酰-辅酶A(DAC-CoA)和巴豆酰基-辅酶A(Crotonyl-CoA)水合反应.计算表明:水合反应以分步机理进行,经历一个烯醇负离子中间体.Glu164残基作为唯一的催化碱/酸参与水合反应,而Glu144虽然没有直接参与反应,但是它能通过氢键作用诱使水分子以合适的朝向活化底物.Crotonyl-CoA底物的水加成活性高于DAC-CoA.Ala98和Gly141与底物羰基之间的氢键作用既有利于底物的准确结合,也能有效稳定反应中形成的过渡态和中间体.另外,Glu144和Glu164周围的氢键网络对于合理维持活性位点排布进而有效促进底物活化也很重要.
The DFT method was used to study the reaction of enoyl-coenzyme A (ECH) catalyzed hydration of 4- (N, N-dimethylamino) -cinnamoyl-CoA and Crotonyl-CoA The calculation shows that the hydration reaction proceeds in a step-by-step mechanism and undergoes an enol negative ion intermediate.Glu164 residues participate in the hydration reaction as the only catalytic base / acid, while Glu144, though not directly involved in the reaction, So that water molecules in the right orientation to activate the substrate.Crotonyl-CoA substrate water-addition activity than DAC-CoA.Ala98 and Gly141 and substrate carbonyl hydrogen bonding between both conducive to the correct substrate, but also Can effectively stabilize the transition state and intermediates formed in the reaction.In addition, the hydrogen bonding network around Glu144 and Glu164 is also very important for maintaining the active site arrangement and effectively activating the substrate.