Comparative Analysis of Structure and Sequences of Oryza sativa Superoxide Dismutase

One of the major classes of antioxidant enzymes, which protect the cellular and subcellular components against harmful reactive oxygen species (ROS), is superoxide dismutase (SOD). SODs play pivotal role in scavenging highly reactive free oxygen radicals and protecting cells from toxic effects. In Oryza sativa three types of SODs are available based on their metal content viz. Cu-Zn SOD, Mn SOD and Fe SOD. In the present study attempts were made to critically assess the structure and phylogenetic relationship among Oryza sativa SODs. The sequence similarity search using local BLAST shows that Mn SODs and Fe SODs have greater degree of similarity compared with that of Cu-Zn SODs. The multiple alignment reveals that seven amino acids were found to be totally conserved. The secondary structure shows that Mn SODs and Fe SODs have similar helixes, sheets, turns and coils compared with that of Cu-Zn SODs. The comparative analysis also displayed greater resemblance in primary, secondary and tertiary structures of Fe SODs and Mn SODs. Comparison between the structure and sequence analysis reveals that Mn SOD and Fe SOD are found to be closely related whereas Cu-Zn SOD evolves independently.