文献类型：期刊文献

英文题名：Disparity in productive binding mode of the slow-reacting enantiomer determines the novel catalytic behavior of Candida antarctica lipase B

作者：Xu, Tao[1]; Zhang, Lujia[1]; Su, Erzheng[1]; Cui, Dongbing[1]; Wang, Xuedong[1]; Wei, Dongzhi[1]

机构：[1] State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China

年份：2010

卷号：62

期号：3-4

起止页码：288

外文期刊名：Journal of Molecular Catalysis B: Enzymatic

收录：EI(收录号：20101312808797)

语种：英文

外文关键词：Candida - Enzymes - Yeast - Reaction kinetics - Molecular modeling - Binding energy - Enantioselectivity - Reaction intermediates - Substrates - Enantiomers

摘要：In the context of specifying the origin of enzyme enantioselectivity, the present study explores the lipase enantioselectivity towards secondary alcohols of similar structure from the perspective of substrate binding. By carrying out molecular mechanics minimization as well as molecular dynamics simulation on tetrahedral reaction intermediates which are used as a model of transition state, we identify an unconventional productive binding mode (PBM)-M/H permutation type for Candida antarctica lipase B (CALB). The in silico results also indicate that different PBMs of the slow-reacting enantiomer do exist in one lipase even when there is little structural differences between substrates, e.g. compounds with Ph or CH2CH2Ph group display the M/H permutation type PBM while molecules with CH2Ph show the M/L permutation type PBM. By relating the PBMs of substrates to the experimentally determined E-values obtained by Hoff et al. [16], we find that disparity in PBM of the slow-reacting enantiomer determines why E-values of substrates with CH2Ph were lower than E-values of substrates with Ph or CH2CH2Ph group. The modeling results also suggest that the " pushed aside" effect of the F atom and Br atom accommodates the medium size substituent of the substrate better in the stereospecificity pocket of the enzyme. ? 2009 Elsevier B.V.