Identification of key residues for pH dependent activation of violaxanthin de-epoxidase from Arabidopsis thaliana.

ABSTRACT: Plants are often exposed to saturating light conditions, which can lead to oxidative stress. The carotenoid zeaxanthin, synthesized from violaxanthin by Violaxanthin De-Epoxidase (VDE) plays a major role in the protection from excess illumination. VDE activation is triggered by a pH reduction in the thylakoids lumen occurring under saturating light. In this work the mechanism of the VDE activation was investigated on a molecular level using multi conformer continuum electrostatic calculations, site directed mutagenesis and molecular dynamics. The pK(a) values of residues of the inactive VDE were determined to identify target residues that could be implicated in the activation. Five such target residues were investigated closer by site directed mutagenesis, whereas variants in four residues

SUBMITTER: Fufezan C 

PROVIDER: S-EPMC3338714 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature