Divergent Spatiotemporal Interaction of Angiotensin Receptor Blocking Drugs with Angiotensin Type1 Receptor

Dhanachandra Singh Khuraijam, Hamiyet Unal, Russell Desnoyer, Sadashiva S Karnik

Index: 10.1021/acs.jcim.7b00424

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Abstract

Crystal structures of the human angiotensin II type 1 receptor (AT1R) complex with the anti-hypertensive agent ZD7155 (PDB id: 4YAY) and the blood pressure medication Benicar (PDB id: 4ZUD) showed that binding poses of both antagonists are similar. This finding implies that clinically used angiotensin receptor blocking (ARB) drugs may interact in a similar fashion. However, clinically observed differences in pharmacological and therapeutic efficacies of ARBs lead to the question whether the dynamic interactions of AT1R with ARBs vary? To address this, we performed induced-fit docking (IFD) of eight clinically used ARBs to AT1R followed by 200 nanosecond molecular dynamic (MD) simulation. The experimental Ki values for ARBs correlated excellently with calculated free energy with R2 = 0.95 and 0.70 for AT1R-ARB models generated respectively by IFD and MD simulation. The eight ARB-AT1R complexes share a common set of binding residues. In addition, MD simulation results validated by mutagenesis data discovered distinctive spatiotemporal interactions that display unique bonding between an individual ARB and AT1R. These findings provide a reasonable broader picture reconciling the structure-based observations with clinical studies reporting efficacy variations for ARBs. The unique differences unraveled for ARBs in this study will be useful for structure-based designing of next generation of more potent and selective ARBs.