In Silico Structural, Virtual Screening and Docking Studies of Human Cytochrome P450 2A7 Protein

Among CYPs, CYP2A sub-family is well known for its function to metabolise xenobiotics. CYP2A includes three members: CYP2A6, CYP2A7 and CYP2A13. Of these three proteins, structure and function of CYP2A6 and CYP2A13 are widely studied, whereas very little study has been carried out on CYP2A7. In the initial in vitro studies on CYP2A7, full protein in its active form could not be expressed. The exact structure and function of CYP2A7 is still not revealed. However, up-regulation of CYP2A7 has been reported in malignant oesophageal cells and colon cancer cells. In the present study, we generated the structure of CYP2A7 protein. The modelled proteins were validated and subjected to molecular docking analyses. The energy and RMSD calculations demonstrated that the protein is highly conserved in nature, i.e., the protein is not much flexible. Here the ligand molecules of NCI Diversity Set II from the ZINC database against the active site of the CYP2A7 protein were screened. Five compounds that possess good inhibitory activity against CYP2A7 active site were identified. The top ranking molecule (ZINC01572309) has a minimum energy score of -12.0 kcal/Mol. This compound is thus a good starting point for further development of strong inhibitors. Our in silico approach could help in better structural and functional analysis of CYP2A7. Apart from structural description of CYP2A7, elaboration of binding sites for inhibitors provides us with an opportunity to utilise binding pockets in targeted inactivation of this protein for further research.