One of the major goals of pharmacogenetics is to elucidate mechanisms and identify patients at increased risk of adverse events (AEs). To date, however, there have been only a few successful examples of this type of approach. In this paper, we describe a retrospective case-control pharmacogenetic study of an AE of unknown mechanism, characterized by elevated levels of serum alanine aminotransferase (ALAT) during long-term treatment with the oral direct thrombin inhibitor ximelagatran. The study was based on 74 cases and 130 treated controls and included both a genome-wide tag single nucleotide polymorphism and large-scale candidate gene analysis. A strong genetic association between elevated ALAT and the MHC alleles DRB1*07 and DQA1*02 was discovered and replicated, suggesting a possible immune pathogenesis. Consistent with this hypothesis, immunological studies suggest that ximelagatran may have the ability to act as a contact sensitizer, and hence be able to stimulate an adaptive immune response.

Ultrastable cyclic peptide frameworks offer great potential for drug design due to their improved bioavailability compared to their linear analogues. Using the sunflower trypsin inhibitor-1 (SFTI-1) peptide scaffold in combination with systematic N-methylation of the grafted pharmacophore led to the identification of novel subtype selective melanocortin receptor (MCR) agonists. Multiple bicyclic peptides were synthesized and tested toward their activity at MC1R and MC3–5R. Double N-methylated compound 18 showed a pKi of 8.73 ± 0.08 (Ki = 1.92 ± 0.34 nM) and a pEC50 of 9.13 ± 0.04 (EC50 = 0.75 ± 0.08 nM) at the human MC1R and was over 100 times more selective for MC1R. Nuclear magnetic resonance structural analysis of 18 emphasized the role of peptide bond N-methylation in shaping the conformation of the grafted pharmacophore. More broadly, this study highlights the potential of cyclic peptide scaffolds for epitope grafting in combination with N-methylation to introduce receptor subtype selectivity in the context of peptide-based drug discovery.

In this study, we performed an extensive exploration of the ligand entry mechanism for members of the steroid nuclear hormone receptor family (androgen receptor, estrogen receptor α, glucocorticoid receptor, mineralocorticoid receptor, and progesterone receptor) and their endogenous ligands. The exploration revealed a shared entry path through the helix 3, 7, and 11 regions. Examination of the x-ray structures of the receptor-ligand complexes further showed two distinct folds of the helix 6-7 region, classified as "open" and "closed", which could potentially affect ligand binding. To improve sampling of the helix 6-7 loop, we incorporated motion modes based on principal component analysis of existing crystal structures of the receptors and applied them to the protein-ligand sampling. A detailed comparison with the anisotropic network model (an elastic network model) highlights the importance of flexibility in the entrance region. While the binding (interaction) energy of individual simulations can be used to score different ligands, extensive sampling further allows us to predict absolute binding free energies and analyze reaction kinetics using Markov state models and Perron-cluster cluster analysis, respectively. The predicted relative binding free energies for three ligands binding to the progesterone receptor are in very good agreement with experimental results and the Perron-cluster cluster analysis highlighted the importance of a peripheral binding site. Our analysis revealed that the flexibility of the helix 3, 7, and 11 regions represents the most important factor for ligand binding. Furthermore, the hydrophobicity of the ligand influences the transition between the peripheral and the active binding site.

We report the primary structure of 4-hydroxyphenylpyruvate dioxygenase [4-hydroxyphenylpyruvate : oxygen oxidoreductase (hydroxylating, decarboxylating)]. The work is based on the isolation of cDNA clones from human liver Agtll libraries. Several overlapping clones covering the coding sequence were characterized. In parallel, peptides from four different digests of the purified protein were analysed for their amino-acid sequence. These peptide sequences covered 86% of the cDNA-derived amino-acid sequence. This gives the sequence for a polypeptide of 392 amino acids with a calculated molecular mass of 44.8 kDa.There is more than 80% identity between the human and the pig enzymes and also between these enzymes and the F antigen from rat and the two allelic forms of this antigen from mouse. The enzyme has 53% conserved amino acids and 27% identical amino acids in common with 4-hydroxyphenylpyruvate dioxygenase from Pseudomonas sp. P. J. 874 and 52% conserved and 28% identical residues, with a protein from Shewanella colwellinna. At the C-terminus there is 61 % identity between the seven proteins. These results indicate that these proteins are all 4-hydroxyphenylpyruvate dioxygenases. The identity of the C-terminus makes this part of the molecule a candidate for a functional role in the catalytic process. At conserved positions in all seven enzymes, there are two tyrosine residues and three histidine residues, i. e. amino acids which have been implicated as ligands for iron in 2-oxoacid-dependent dioxygenases. The gene encoding the enzyme was localized to chromosome 12q14 + qter by Southern-blot analysis of human-rodent somatic-cell hybrids.

5-Lipoxygenase activating protein (FLAP) inhibitors attenuate 5-lipoxygenase pathway activity and reduce the production of proinflammatory and vasoactive leukotrienes. As such, they are hypothesized to have therapeutic benefit for the treatment of diseases that involve chronic inflammation including coronary artery disease. Herein, we disclose the medicinal chemistry discovery and the early clinical development of the FLAP inhibitor AZD5718 (12). Multiparameter optimization included securing adequate potency in human whole blood, navigation away from Ames mutagenic amine fragments while balancing metabolic stability and PK properties allowing for clinically relevant exposures after oral dosing. The superior safety profile of AZD5718 compared to earlier frontrunner compounds allowed us to perform a phase 1 clinical study in which AZD5718 demonstrated a dose dependent and greater than 90% suppression of leukotriene production over 24 h. Currently, AZD5718 is evaluated in a phase 2a study for treatment of coronary artery disease.