Pinpointing a mechanistic switch between ketoreduction and ‘ene’-reduction in short chain dehydrogenases/reductases

Research output: Contribution to journalArticle

  • External authors:
  • Antonios Lygidakis
  • Vijaykumar Karuppiah
  • Robin Hoeven
  • Aisling Ni Cheallaigh
  • Helen Toogood


Three enzymes of the Mentha essential oil biosynthetic pathway are highly homologous, namely the ketoreductases (−)-menthone:(−)-menthol reductase and (−)-menthone:(+)-neomenthol reductase, and the “ene” reductase isopiperitenone reductase. We identified a rare catalytic residue substitution in the last two, and performed comparative crystal structure analyses and residue-swapping mutagenesis to investigate whether this determines the reaction outcome. The result was a complete loss of native activity and a switch between ene reduction and ketoreduction. This suggests the importance of a catalytic glutamate vs. tyrosine residue in determining the outcome of the reduction of α,β-unsaturated alkenes, due to the substrate occupying different binding conformations, and possibly also to the relative acidities of the two residues. This simple switch in mechanism by a single amino acid substitution could potentially generate a large number of de novo ene reductases.

Bibliographical metadata

Original languageEnglish
Pages (from-to)9596-9600
Number of pages5
JournalAngewandte Chemie
Issue number33
Early online date13 Jul 2016
StatePublished - 8 Aug 2016

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