Anales RANF

S18-02 INTEGRATED APPROACHES TO MODEL THE CONFORMATIONAL EQUILIBRIUM AND THE LIGAND OPTIMIZATION ON ADENOSINE RECEPTORS Hugo Gutiérrez de Terán Dept. of Cell and Molecular Biology, Uppsala University, BMC, Box 596, SE-751 24 Uppsala (Sweden) In this talk, I will introduce our GPCR modeling and simulation approaches to explore ligand binding affinities, within the scope of structure-affinity relationships (SAR), on one side, and to characterize the effect of single point mutations (commonly coming from site-directed mutagenesis, SDM). I will show how this approach can provide a mapping of the key receptor-ligand interactions that aided in the design of novel chemotyper for the family of adenosine receptor. The new structural landscape of GPCRs provides an excellent starting point to model receptor ligand interactions, either with experimental structures of the receptor of interest, either obtaining high quality homology models. For this, in our lab we have developed the GPCR-ModSim web server, which allows the homology modeling and MD simulation of any GPCR of interest. Once the structure of the receptor-ligand complex is clear, we have developed protocols via advanced free energy perturbation (FEP) simulations to quantitatively and routinely assess the effects of point-mutations on ligand binding as well as the SAR of congeneric series of ligands. The characterization of These data can be mapped into the structure of the receptor using computational modeling, providing the most complete picture of the molecular interactions responsible of high affinity and selectivity.Our method is based on an efficient molecular dynamics (MD) sampling of the protein-ligand binding site using spherical boundary conditions, and is now automated as part of our open source MD software Q. and FEP simulation protocols and present recent applications on adenosine receptors. I will focus on three recent achievements with important methodological and practical applications: 1) The conformational selectivity of agonists and antagonists for the active and inactive forms of the A2A and A2B receptors; 2) The optimized design of A 2B antagonists derived from ISAM140 (currently commercialized as a reference antagonist). 3) and the recent series of A 2A antagonists initially reported by the company Sosei-Heptares, where our FEP-guided design allowed the synthesized, pharmacologically characterization and co-crystallization with the A 2A receptor of two antagonists, confirming the initial modeling hypothesis. Our methodology is freely available under http://open.gpcr-modsim.org/ and https://github.com/qusers/Q6 [1] a) Keranen, H.; Aqvist, J.; Gutierrez-de-Teran, H. Chem Comm (2015), 51:3522; b) Boukharta, L.; Gutierrez-de-Teran, H.; Aqvist, J. PlOS Comp. Biol (2014) 10:e1003585 [2] Jespers, W.et al. and Gutiérrez-de-Terán H. Trends Pharmacol. Sci. (2018) 39:75-89 [3] Esguerra, M. et al. and Gutiérrez-de-Terán, H. Nucl. Ac. Res. (2016) 44: W455-62 [5] El Maatougui, A., Azuaje, et al. and Gutiérrez-de-Terán, J Med Chem. (2016) 59:1967.