Analysis of Electronic Structure of Photoactive Yellow Protein by Canonical Molecular Orbitals Calculation

Abstract

Photoactive Yellow Protein (PYP) is a 125-residue photoreceptor protein that contains p-coumaric acid (pCA) as the active center. In the early stages of the photoreaction cycle, the pCA undergoes the trans-cis isomerization reaction. In order to understand mechanism of the photo-isomerization reaction by the electronic structure, the canonical molecular orbital calculation of pCA and the 35-residue model was carried out. We observed the molecular orbitals involved in the photo-isomerization reaction, which was spreading into the surrounding proteins from the active site.