异构化
化学
立体化学
异构酶
黄素组
立体选择性
催化作用
酶催化
光化学
酶
有机化学
作者
Marina Simona Robescu,Laura Cendron,Arianna Bacchin,Karla Wagner,Tamara Reiter,Ignacy Janicki,Kemal Merusic,Maximilian Illek,Matteo Aleotti,Elisabetta Bergantino,Mélanie Hall
标识
DOI:10.1021/acscatal.2c01110
摘要
Native and promiscuous catalytic activities of flavin-dependent Old Yellow Enzymes (OYEs) reported to date are initiated by the reduced flavin upon electron transfer. As a rare exception, the isomerization of a nonactivated C═C bond was shown to be hydride-independent with two nonstereoselective yeast OYEs. Here, we report the asymmetric isomerization of a prochiral model substrate, γ-methyl β,γ-butenolide, to the corresponding (R)- and (S)-enantiomers of the γ-methyl α,β-butenolide in up to >99% ee by two stereocomplementary OYEs of algal and fungal origin, respectively, which operate by asymmetric proton transfer. Mechanistic studies based on two newly solved crystal structures, along with soaking experiments and site-directed mutagenesis, support the crucial role of partially nonconserved tyrosine residues for the activity and stereoselectivity of both (R)- and (S)-isomerases. This study offers a unique view on the potential of flavoproteins in nonredox catalysis and provides hints for scouting olefin isomerases in likely stereodivergent classes of OYEs.
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