Lanosterol Biosynthesis: The Critical Role of the Methyl-29 Group of 2,3-Oxidosqualene for the Correct Folding of this Substrate and for the Construction of the Five-Membered D Ring
作者:Tsutomu Hoshino、Akifumi Chiba、Naomi Abe
DOI:10.1002/chem.201201779
日期:2012.10.8
Lanosterol synthase catalyzes the polycyclization reaction of (3S)‐2,3‐oxidosqualene (1) into tetracyclic lanosterol 2 by folding 1 in a chair‐boat‐chair‐chair conformation. 27‐Nor‐ and 29‐noroxidosqaulenes (7 and 8, respectively) were incubated with this enzyme to investigate the role of the methyl groups on 1 for the polycyclization cascade. Compound 7 afforded two enzymatic products, namely, 30‐norlanosterol
羊毛甾醇合酶通过将1折叠成椅子-椅子-椅子-构象,催化(3 S)-2,3-氧化角鲨烯(1)变成四环羊毛甾醇2的多环化反应。将27-Nor-和29-Noroxidosqaulenes(分别为7和8)与该酶一起孵育,以研究1上的甲基在多环化级联反应中的作用。化合物7得到两个酶产物,即30-norlanosterol(12)和26-normalabaricatriene(13 ; 12 / 139:1),分别通过正常的椅子-椅子-椅子构造和非典型的椅子-椅子-构造构造而成。化合物8得到两个产物14和15(14 / 15 4:5),这是由正常的和不寻常的polycyclization通路通过一个椅子椅的船形椅式构象中分别产生,。值得注意的是,B形圈的麻花船结构被改为15代时在能量上很受青睐的椅子结构。令人惊讶的是14和15由一个新颖的6,6,6,6-稠合的四环系统组成,因此不同于6,6,6,5-稠