Molecular dynamics simulation on vasopressin and its analogs with different activity

Abstract

To study the biological active conformation of Anti-Dieuretic Hormone(ADH) Vasopressin, we carry out molecular dynamics simulations coupled with heating and annealing procedure. We investigate the relationship between various ADH analoges and their diversities of activity using RMS fluctuation of each residue and the torsion angle of disulfide bond in vacuum state. The fluctuation of $Tyr^2$ in desmopressin is higher than other analogs including with 8-Arg vasopressin. this fluctuation of $Tyr^2$ makes an favorable to V2 receptor. Disulfide torsion angle of analogs is changed usually left-handed($-100^\circ\,\sim\,-90^\circ$), although initial structure was the same right-handed($98^\circ$). As for proposed from oxytocin, the fact det ermining agonist or antagonist is left-handed or right-handed form, is not applicated in vasopressin analogs. It is found that this small change in the sequence of amino acids make a large conformational fluctuation, and this affect on the drug activity. It is expected that this kind of approach motivates designing drug without X-ray Crystallography structure of receptor.