In silico 3D structure prediction and hydrogen peroxide binding study of wheat catalase

Catalase (CAT) is one of the most active enzyme catalysts found in plants, animals and in all aerobic microorganisms. The major function of the enzyme is to decompose H2O2, produced by cellular metabolic activities under normal and stressful conditions to water and oxygen. The present study involves 3D structure modeling of wheat catalase from Triticum aestivum by MODELLER9v7 and its binding study with H2O2. The Evaluation of the model was based on Discrete Optimized Protein Energy Score (DOPE). The structure was also validated using PROCHECK comprising of 95.0% amino acid residues in favored regions of Ramachandran plot, Verify3D and ProsA which confirm that the model is reliable. The 3D model of the molecule was found to consist of ten strands and seventeen helices having a common fold characterised by β-pleated sheet flanked either side by helices. The docking study with H2O2 indicates that Gln352 and Arg353 are two important determinant residues in binding H2O2 as these residues have strong hydrogen bonding contacts with the substrate. These hydrogen-bonding interactions play a significant role in the stability of the complex.