Theoretical Modeling and Docking Studies of Silkworm Serotonin Receptor

The Silkworm serotonin receptor protein is an integral membrane protein which belongs to the largest superfamily of G protein-coupled receptors that communicate signals across the cell membrane through their interaction with heterotrimeric G proteins and regulate many of the physiological processes including the regulation of feeding, aggression, mood, perception, pain, anxiety etc. Despite the importance of serotonin receptor protein its structure have not yet determined experimentally due to difficulty in crystallization. The three-dimensional structure was modelled by the MODELLER program using the template rh1A which has 33% identity. The modelled structure was validated using Procheck and Ramachandran plot. It was found that the percentage of residue lying in the most favoured regions, additionally allowed regions, generously allowed regions, disallowed regions are 93.3%, 6.4%, 0% and 0.3%, respectively and it indicates reasonably good model. The overall Procheck G-factor and overall quality factor of ERRAT graph were 0.04 and 80.759, respectively. The binding site of the serotonin receptor protein was predicted using Q-Sitefinder and the interaction studies carried out with serotonin, agonist and reveals that the seven interaction residues Asp141, Val142, Gln218, Thr227, Ser230, Phe382, Leu405 of serotonin receptor protein interact with the serotonin form three hydrogen bond. This study provides a structural understanding at the atomic level of three-dimensional structure of silkworm serotonin receptor protein and their binding-sites and to elucidate of many promising active lead compounds.