RT Journal Article SR Electronic T1 Exploring the kinetic selectivity of drugs targeting the β1-adrenoceptor JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.08.31.458064 DO 10.1101/2021.08.31.458064 A1 David A. Sykes A1 Mireia Jiménez-Rosés A1 John Reilly A1 Robin A. Fairhurst A1 Steven J. Charlton A1 Dmitry B. Veprintsev YR 2021 UL http://biorxiv.org/content/early/2021/08/31/2021.08.31.458064.abstract AB In this study, we report the β1-adrenoceptor binding kinetics of several clinically relevant β1/2-adrenoceptor (β1/2AR) agonists and antagonists. We demonstrate that the physicochemical properties of a molecule directly affect its kinetic association rate (kon) and affinity for the target. In contrast to our findings at the β2-adrenoceptor, a drug’s immobilized artificial membrane partition coefficient (KIAM), reflecting both hydrophobic and electrostatic interactions of the drug with the charged surface of biological membranes, was no better predictor than simple hydrophobicity measurements such as log P or logD7.4, characterized by a distribution between water and a non-aqueous organic phase (e.g. n-octanol) at predicting association rate. Overall, this suggests that hydrophobic interactions rather than a combination of polar and hydrophobic interactions play a more prominent role in dictating the binding of these ligands to the β1-adrenoceptor.Using a combination of kinetic data, detailed structural and physicochemical information we rationalize the above findings and speculate that the association of positively charged ligands at the β1AR is curtailed somewhat by its predominantly neutral/positive charged extracellular surface. Consequently, hydrophobic interactions in the ligand binding pocket dominate the kinetics of ligand binding. In comparison at the β2AR, a combination of hydrophobicity and negative charge attracts basic, positively charged ligands to the receptor’s surface promoting the kinetics of ligand binding. Additionally, we reveal the potential role kinetics plays in the on-target and off-target pharmacology of clinically used β-blockers.Competing Interest StatementSJC is a founder of Excellerate Bioscience Ltd a CRO. DAS and DBV are both founders of Z7 Biotech Ltd a CRO. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.CHOChinese hamster ovaryHBSSHanks’ balanced salt solution[3H]-DHA1-[4,6-propyl-3H] dihydroalprenololNSBnon-specific binding.