Structural and Functional analysis of glutathione peroxidase from Ricinus communis L.– a computational approach.

Oxidative stress in plants causes the induction of several enzymes, including superoxidedismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2). Thefirst two are responsible for converting superoxide to H2O2 and its subsequent reduction to H2O, and thethird is involved in recycling of ascorbate. Glutathione peroxidases (GPXs, EC 1.11.1.9) are a family of keyenzymes involved in scavenging oxyradicals in animals. Only recently, indications for the existence of thisenzyme in plants were reported. Genes with significant sequence homology to one member of the animalGPX family, namely phospholipid hydroperoxide glutathione peroxidase (PHGPX), were isolated fromseveral plants. In this paper we report the homology modelling of the glutathione peroxidase protein fromRicinus communis L. and its interactions with its two substrates hydrogen peroxide and glutathione. Specificsites of interaction were identified and ligand binding pockets were also screened.