Segura Michael J R, Lodeiro Silvia, Meyer Michelle M, Patel Akash J, Matsuda Seiichi P T
Department of Chemistry, Rice University, Houston, Texas 77005, USA.
Org Lett. 2002 Dec 12;4(25):4459-62. doi: 10.1021/ol0269897.
[reaction: see text] Cycloartenol synthase cyclizes and rearranges oxidosqualene to the protosteryl cation and then specifically deprotonates from C-19. To identify mutants that deprotonate differently, randomly generated mutant cycloartenol synthases were selected in a yeast lanosterol synthase mutant. A novel His477Asn mutant was uncovered that produces 88% lanosterol and 12% parkeol. The His477Gln mutant produces 73% parkeol, 22% lanosterol, and 5% Delta(7)-lanosterol. These are the most accurate lanosterol synthase and parkeol synthase that have been generated by mutagenesis.
[反应：见正文] 环阿屯醇合酶将氧化角鲨烯环化并重排为原甾醇阳离子，然后从C-19位特异性地脱去质子。为了鉴定脱质子方式不同的突变体，在酵母羊毛甾醇合酶突变体中筛选随机产生的突变型环阿屯醇合酶。发现了一种新型的His477Asn突变体，其产生88%的羊毛甾醇和12%的帕克醇。His477Gln突变体产生73%的帕克醇、22%的羊毛甾醇和5%的Δ(7)-羊毛甾醇。这些是通过诱变产生的最精确的羊毛甾醇合酶和帕克醇合酶。
