The p38 MAP kinase plays a crucial role in regulating the production of proinflammatory cytokines, such as tumor necrosis factor and interleukin-1. Blocking this kinase may offer an effective therapy for treating many inflammatory diseases. Here we report a new allosteric binding site for a diaryl urea class of highly potent and selective inhibitors against human p38 MAP kinase. The formation of this binding site requires a large conformational change not observed previously for any of the protein Ser/Thr kinases. This change is in the highly conserved Asp-Phe-Gly motif within the active site of the kinase. Solution studies demonstrate that this class of compounds has slow binding kinetics, consistent with the requirement for conformational change. Improving interactions in this allosteric pocket, as well as establishing binding interactions in the ATP pocket, enhanced the affinity of the inhibitors by 12,000-fold. One of the most potent compounds in this series, BIRB 796, has picomolar affinity for the kinase and low nanomolar inhibitory activity in cell culture.

We report on a series of N-pyrazole, N'-aryl ureas and their mode of binding to p38 mitogen activated protein kinase. Importantly, a key binding domain that is distinct from the adenosine 5'-triphoshate (ATP) binding site is exposed when the conserved activation loop, consisting in part of Asp168-Phe169-Gly170, adopts a conformation permitting lipophilic and hydrogen bonding interactions between this class of inhibitors and the protein. We describe the correlation of the structure-activity relationships and crystallographic structures of these inhibitors with p38. In addition, we incorporated another binding pharmacophore that forms a hydrogen bond at the ATP binding site. This modification affords significant improvements in binding, cellular, and in vivo potencies resulting in the selection of 45 (BIRB 796) as a clinical candidate for the treatment of inflammatory diseases.

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Background: MIF is a pro-inflammatory cytokine implicated in autoimmune diseases. Results: A small molecule that binds to MIF and inhibits its cytokine activities was identified. Conclusion:The inhibitor binds in a unique region on MIF and reveals a new way to block the cytokine activities of MIF. Significance: The inhibitor is a valuable tool to design MIF-directed therapeutics for inflammatory diseases.

We report on the structure-activity relationships (SAR) of 1-(5-tert-butyl-2-p-tolyl-2H-pyrazol-3-yl)-3-[4-(2-morpholin-4-yl-ethoxy)naphthalen-1-yl]urea (BIRB 796), an inhibitor of p38alpha MAP kinase which has advanced into human clinical trials for the treatment of autoimmune diseases. Thermal denaturation was used to establish molecular binding affinities for this class of p38alpha inhibitors. The tert-butyl group remains a critical binding element by occupying a lipophilic domain in the kinase which is exposed upon rearrangement of the activation loop. An aromatic ring attached to N-2 of the pyrazole nucleus provides important pi-CH(2) interactions with the kinase. The role of groups attached through an ethoxy group to the 4-position of the naphthalene and directed into the ATP-binding domain is elucidated. Pharmacophores with good hydrogen bonding potential, such as morpholine, pyridine, and imidazole, shift the melting temperature of p38alpha by 16-17 degrees C translating into K(d) values of 50-100 pM. Finally, we describe several compounds that potently inhibit TNF-alpha production when dosed orally in mice.

The p38 mitogen activated protein (MAP) kinase is an integral enzyme involved in the production of a wide variety of pro-inflammatory cytokines from various cell types. The identification of this kinase and of the diaryl imidazole containing inhibitor, SB203580, initiated an intense discovery effort in this field. Numerous inhibitors were subsequently produced containing replacements for the imidazole, as well as some of the pharmacophores attached to it. During this time many other classes of potent p38 inhibitors emerged containing scaffolds and binding components not found in the diaryl imidazole group. This review summarizes nine of those classes. At least one of these classes requires the kinase to undergo reorganization prior to binding. From this diverse set of inhibitors four compounds have been reported advancing into human clinical trials.

N-Linkcd glycopeptides were synthesized by condensation of a highmannose anomeric aniine bearing a pentasaccharidc with aspartic-acid-containing tri-and pentapcptides through the agency of IIDQ. The pentasaccharide portion, corresponding to the "core" region of all asparagine-linked glycoproteins, was assembled by means of glycal-derived thioethyl donors and glycal acceptors. The central mannose residue was established by inversion of the C 2 hydroxyl of a glucosyl precursor in the pentasaccharide.The protecting-group scheme employed allows the extension of Keywords * glycopeptides glycons * omannosides -oligosaccharides the pentasaccharide through the tcrminal mannose units. While a fully convergent coupling of the high-mannose carbohydrate to the peptide domain has thus bccn accomplished for the first time with a fully synthetic sugar, the stereochemical integrity of the anomeric center of the carbohydrate domain was not maintained and a mixture of glycopeptides was obtained.

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