Coniferyl Alcohol Radical Detection by the Dirigent Protein AtDIR6 Monitored by EPR

Chembiochem. 2021 Mar 16;22(6):992-995. doi: 10.1002/cbic.202000650. Epub 2020 Nov 24.

Abstract

Plant dirigent proteins (DIRs) control the stereoselectivity of the monolignol coniferyl alcohol radical coupling. The main mechanistic hypothesis on this chemo- and stereoselective reaction invokes a binding of coniferyl alcohol radical substrates in the dirigent protein active site so that only one enantiomeric form can be produced. We have studied the influence of the Arabidopsis thaliana AtDIR6 protein on the transient coniferyl alcohol radical by EPR. Herein, we show that AtDIR6 stabilizes coniferyl alcohol radicals prior to directing their coupling towards the formation of (-)-pinoresinol.

Keywords: EPR; UV light; dirigent proteins; radicals; stereoselectivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / metabolism*
  • Catalytic Domain
  • Electron Spin Resonance Spectroscopy*
  • Free Radicals / analysis*
  • Oxidation-Reduction / radiation effects
  • Phenols / chemistry*
  • Stereoisomerism
  • Ultraviolet Rays

Substances

  • Arabidopsis Proteins
  • DIR6 protein, Arabidopsis
  • Free Radicals
  • Phenols
  • coniferyl alcohol