Application of Fragment Molecular Orbital Method to investigate dopamine receptors

GPCRs are a vast family of seven-domain transmembrane proteins. This family includes dopamine receptors (D1, D2, D3, D4, and D5), which mediate the variety of dopamine-controlled physiological functions in the brain and periphery. Ligands of dopamine receptors are used for managing several neuropsychiatric disorders, including bipolar disorder, schizophrenia, anxiety, and Parkinson’s disease. Recent studies have revealed that dopamine receptors could be part of multiple signaling cascades, rather than of a single signaling pathway. For these targets, a variety of experimental and computational drug design techniques are utilized. In this work, dopamine receptors D2, D3, and D4 were investigated using molecular dynamic method as well as computational ab initio Fragment Molecular Orbital method (FMO), which can reveal atomistic details about ligand binding. The results provided useful insights into the significances of amino acid residues in ligand binding sites. Moreover, similarities and differences between active-sites of three studied types of receptors were examined.