Abstract P250: Unveiling Binding Pocket Structure Of Mas Receptor And Its Interaction With Angiotensin-(1-7)

Abstract

Substantial amount of preclinical data points out Mas receptor as a promising pharmacological target to treat cardiovascular diseases. Here, we aimed to characterize Mas binding pocket and its interaction with Angiotensin-(Ang)-1-7, in order to provide insights for potential structure-based drug discovery. Homology modeling based on AT1 and AT2 crystal structures, combined with peptide docking (Schrodinger TM ) and molecular dynamics simulations (Gromacs) were employed to generate hypothesis about crucial interactions in protein-ligand complex. Proposed model was further validated in vitro using HEK cells transiently transfected with wild-type Mas or mutant Mas (Arg245Ala). Mas-receptor activation was assessed by FOXO1 dephosphorylation at Ser256 after 5 minutes incubation with Ang-1-7 (10 -7 M). Model of Mas/Ang-(1-7) complex revealed electrostatic interaction between Ang-(1-7) C-terminus and Mas Arg245. Interestingly, while Ang-1-7 incubation reduced FOXO1 phosphorylation by 35 % in HEK-Mas wild type (1.000 vs. 0.654 A.U., p<0.01, n=8), this effect was abolished in HEK-Mas mutant (1.000 vs. 0.990 A.U., n.s. , n=5). In sum, Arg245 of Mas is essential for the receptor activation, which is in accordance with A-779 antagonism (C-terminus modification of Ang-(1-7)), endorsing our proposed structure model. Further elucidation of the ligand-receptor interactions may drive rational drug discovery and lead to development of improved strategies for Mas targeting.