Directed evolution experiments reveal mutations at cycloartenol synthase residue His477 that dramatically alter catalysis
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Updated: Sep 28, 2026

Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening
Published on: April 1, 2016
Michael J R Segura1, Silvia Lodeiro, Michelle M Meyer
1Department of Chemistry, Rice University, Houston, Texas 77005, USA.
Abstract:
[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.
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