Characterization and Analyses of Hydrophobic Clusters, Acetylation and Myristoylation Sites in Plant Glutathione Peroxidase Sequences

Incomplete reduction of oxygen molecules is the primary source for the formation of reactive oxygen species (ROS) during cytosolic metabolism or mitochondrial respiration. These phenomenons may be as a result of biotic or abiotic stress. Exposure to exogenous stimuli such as radiation might be an alternative pathway of ROS production. Thus plants require counter defense strategies to combat the increase of this toxic molecular build up in its cell cytoplasm. As a result they have devised an army of free radical scavenging enzymes which enable them to dissipate the oxidative stress imposed by the accumulation of these toxic moieties. Glutathione Peroxidase forms an important part of this arms race along with several catalases and organelle specific enzymes such as superoxide dismutase. Plant glutathione peroxidases (GPXs) have been studied exclusively for their evolutionary lineages since they represent a hybrid class of molecules in context of the presence and absence of selenocysteine at their catalytic centres, the former situation predominant in non vascular plant groups while the later a predominant feature of vascular plants. This analysis focuses on three important aspects of protein structure analyses – hydrophobic cluster analyses for identification of homologues, and acetylation and myristoylation sites which provide us with information regarding the post translational modifications of a particular protein group. Specific patterns of clusters along with acetylation and myristoylation site frequencies were obtained which indicate that GPXs of non vascular plant members possess less chances of getting myristoylated while acetylation was predominant in most land plant lineages but absent in aquatic members.