Stereospecific Formation of <i>E</i>- and <i>Z</i>-Disubstituted Double Bonds by Dehydratase Domains from Modules 1 and 2 of the Fostriecin Polyketide Synthase
作者:Dhara D. Shah、Young-Ok You、David E. Cane
DOI:10.1021/jacs.7b08896
日期:2017.10.11
shown to catalyze the NADPH-dependent stereospecific reduction of 3-ketobutyryl-FosACP2 (23) to (3S)-3-hydroxybutyryl-FosACP2 (8). Consistent with this finding, FosDH2 catalyzed the interconversion of the corresponding triketide substrates (3R,4E)-3-hydroxy-4-hexenoyl-FosACP2 (18) and (2Z,4E)-2,4-hexadienoyl-FosACP2 (21). FosDH2 also catalyzed the stereospecific hydration of (Z)-2-butenoyl-FosACP2 (14)
邻苯二酚聚酮合酶(PKS)模块1的脱水酶结构域FosDH1催化了(3 R)-3-羟基丁酰-FosACP1(5)和(E)-2-丁烯酰基-FosACP1(11)的立体有择互变。直接LC-MS / MS和手性GC-MS的组合。FosDH1既不作用于(3 S)-3-羟基丁酰基-FosACP1(6)也不作用于(Z)-2-丁烯酰基-FosACP1(12)。研究显示,FosKR2是一种从邻苯二酸PKS的模块2还原而来的酮还原酶,通常可为FosDH2提供天然底物,该酶可催化NADPH依赖性的3-酮丁酰-FosACP2(23)立体定向还原至(3 S)-3-羟基丁酰基-FosACP2(8)。符合这一发现,FosDH2催化了相应的三酮化合物底物(3 R,4 E)-3-羟基-4-己烯酰基-FosACP2(18)和(2 Z,4 E)-2,4-己二烯酰基-FosACP2的相互转化(21)。FosDH2还催化了(Z)-