Fatty acid amide hydrolase (FAAH) degrades neuromodulating fatty acid amides including anandamide (endogenous cannabinoid agonist) and oleamide (sleep-inducing lipid) at their sites of action and is intimately involved in their regulation. Herein we report the discovery of a potent, selective, and efficacious class of reversible FAAH inhibitors that produce analgesia in animal models validating a new therapeutic target for pain intervention. Key to the useful inhibitor discovery was the routine implementation of a proteomics-wide selectivity screen against the serine hydrolase superfamily ensuring selectivity for FAAH coupled with systematic in vivo examinations of candidate inhibitors.

The critical issues in docking include the prediction of the correct binding pose and the accurate estimation of the corresponding binding affinity. Different docking methodologies have all been successful in reproducing the crystallographic binding modes but struggle when predicting the corresponding binding affinities. The aim of this work is to evaluate the performance of the MM-GB/SA rescoring of docking poses in structure-based lead optimization. To accomplish that, a diverse set of pharmaceutically relevant targets, including CDK2, FactorXa, Thrombin, and HIV-RT were selected. The correlation between the MM-GB/SA results and experimental data in all cases is remarkable. It even qualifies this approach as a more attractive alternative for rank-ordering than the Free Energy Perturbation and Thermodynamic Integration methodologies because, while as accurate, it can handle more structurally dissimilar ligands and provides results at a fraction of the computational cost. On the technical side, the benefit of performing a conformational analysis and having an ensemble of conformers to represent each ligand in the unbound state during the MM-GB/SA rescoring procedure was investigated. In addition, the estimation of conformational entropy penalties for the ligands upon binding, computed from the Boltzmann distribution in water, was evaluated and compared to a commonly used approach employed by many docking scoring functions.

The eukaryotic initiation factor 4E (eIF4E) plays a central role in the initiation of gene translation and subsequent protein synthesis by binding the 5' terminal mRNA cap structure. We designed and synthesized a series of novel compounds that display potent binding affinity against eIF4E despite their lack of a ribose moiety, phosphate, and positive charge as present in m7-GMP. The biochemical activity of compound 33 is 95 nM for eIF4E in an SPA binding assay. More importantly, the compound has an IC(50) of 2.5 μM for inhibiting cap-dependent mRNA translation in a rabbit reticular cell extract assay (RRL-IVT). This series of potent, truncated analogues could serve as a promising new starting point toward the design of neutral eIF4E inhibitors with physicochemical properties suitable for cellular activity assessment.

Fatty acid amide hydrolase (FAAH) is a serine hydrolase responsible for the degradation of anandamide, an endogenous cannabinoid agonist, and oleamide, a sleep-inducing lipid. Recently, Boger and co-workers reported a potent, selective, and efficacious class of reversible alpha-ketoheterocycle inhibitors of FAAH that produce analgesia in animal models (J. Med. Chem. 2005, 48, 1849-1856; Bioorg. Med. Chem. Lett. 2005, 15, 1423-1428). Key aspects of the structure-activity data are addressed here through computational analysis of FAAH inhibition using Monte Carlo (MC) simulations in conjunction with free energy perturbation (FEP) calculations. The MC/FEP simulations demonstrate that incorporation of pyridine at the C5 position of the 2-keto-oxazole and 2-keto-1,3,4-oxadiazole derivatives significantly enhances binding affinity by formation of a hydrogen-bonded array between the pyridyl nitrogen and Lys142 and Thr236. The results also attribute the activity boost upon substitution of oxazole by oxadiazole to reduced steric interactions in the active site and a lower torsional energy penalty upon binding.