RESUMEN
We determine and compare the crystal structure of two proteases belonging to the subtilisin superfamily: S41, a cold-adapted serine protease produced by Antarctic bacilli, at 1.4 A resolution and Sph, a mesophilic serine protease produced by Bacillus sphaericus, at 0.8 A resolution. The purpose of this comparison was to find out whether multiple calcium ion binding is a molecular factor responsible for the adaptation of S41 to extreme low temperatures. We find that these two subtilisins have the same subtilisin fold with a root mean square between the two structures of 0.54 A. The final models for S41 and Sph include a calcium-loaded state of five ions bound to each of these two subtilisin molecules. None of these calcium-binding sites correlate with the high affinity known binding site (site A) found for other subtilisins. Structural analysis of the five calcium-binding sites found in these two crystal structures indicate that three of the binding sites have two side chains of an acidic residue coordinating the calcium ion, whereas the other two binding sites have either a main-chain carbonyl, or only one acidic residue side chain coordinating the calcium ion. Thus, we conclude that three of the sites are of high affinity toward calcium ions, whereas the other two are of low affinity. Because Sph is a mesophilic subtilisin and S41 is a psychrophilic subtilisin, but both crystal structures were found to bind five calcium ions, we suggest that multiple calcium ion binding is not responsible for the adaptation of S41 to low temperatures.
Asunto(s)
Bacillus/enzimología , Subtilisinas/química , Animales , Calcio/metabolismo , Dominio Catalítico , Frío , Cristalografía por Rayos X , Modelos Moleculares , Unión Proteica , Subtilisinas/metabolismoRESUMEN
This communication details the synthesis, biological activity, and binding mode of a novel class of 2-benzimidazole substituted pyrimidines. The most potent analogs disclosed showed low nanomolar activity for the inhibition of Lck kinase and a representative analog was co-crystallized with Hck (a structurally related member of the Src family kinases).
Asunto(s)
Bencimidazoles/química , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Pirimidinas/química , Enlace de Hidrógeno , Concentración 50 Inhibidora , Interleucina-2/metabolismo , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/síntesis química , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/metabolismo , Estructura Molecular , Inhibidores de Proteínas Quinasas/química , Proteínas Proto-Oncogénicas c-hck/química , Proteínas Proto-Oncogénicas c-hck/metabolismo , Relación Estructura-ActividadRESUMEN
A series of C-2, C-8, and N-9 trisubstituted purine based inhibitors of TNF-alpha production are described. The most potent analogs showed low nanomolar activity against LPS-induced TNF-alpha production in a THP-1 cell based assay. The SAR of the series was optimized with the aid of X-ray co-crystal structures of these inhibitors bound with mutated p38 (mp38).
Asunto(s)
Purinas/química , Factor de Necrosis Tumoral alfa/química , Línea Celular , Química Farmacéutica , Cristalografía por Rayos X , Diseño de Fármacos , Humanos , Lipopolisacáridos/química , Modelos Químicos , Modelos Moleculares , Proteínas Quinasas p38 Activadas por Mitógenos/química , Proteínas Quinasas p38 Activadas por Mitógenos/genéticaRESUMEN
A new class of tumor necrosis factor alpha (TNF-alpha) synthesis inhibitors based on an N-2,4-pyrimidine-N-phenyl-N'-phenyl urea scaffold is described. Many of these compounds showed low-nanomolar activity against lipopolysaccharide stimulated TNF-alpha production. X-ray co-crystallization studies with mutated p38alpha showed that these trisubstituted ureas interact with the ATP-binding pocket in a pseudo-bicyclic conformation brought about by the presence of an intramolecular hydrogen bonding interaction.
Asunto(s)
Compuestos de Fenilurea/química , Compuestos de Fenilurea/farmacología , Pirimidinas/química , Pirimidinas/farmacología , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adenosina Trifosfato/química , Sitios de Unión , Cristalografía por Rayos X , Enlace de Hidrógeno , Lipopolisacáridos/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Modelos Moleculares , Estructura Molecular , Compuestos de Fenilurea/clasificación , Pirimidinas/clasificación , Estereoisomerismo , Relación Estructura-Actividad , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
4-Aryl-5-pyrimidyl based cytokine synthesis inhibitors that contain a novel monocyclic, pyrazolone heterocyclic core are described. Many of these inhibitors showed low nanomolar activity against LPS-induced TNF-alpha production. One of the compounds (6e) was found to be efficacious in the rat iodoacetate (RIA) in vivo model of osteoarthritis. The X-ray crystal structure of a pyrazolone inhibitor cocrystallized with mutated p38 (mp38) is presented.
Asunto(s)
Citocinas/antagonistas & inhibidores , Citocinas/biosíntesis , Pirazolonas/síntesis química , Pirazolonas/farmacología , Animales , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Cinética , Lipopolisacáridos/farmacología , Modelos Moleculares , Conformación Molecular , Osteoartritis/prevención & control , Pirazolonas/química , Ratas , Relación Estructura-Actividad , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/biosíntesis , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidoresRESUMEN
4-Aryl-3-pyridyl and 4-aryl-3-pyrimidinyl based tumor necrosis factor-alpha (TNF-alpha) inhibitors, which contain a novel isoxazolone five-membered heterocyclic core are described. Many showed sub-micromolar activity against lipopolysaccharide-induced TNF-alpha production.
Asunto(s)
Isoxazoles/síntesis química , Isoxazoles/farmacología , Pirimidinas/síntesis química , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Acetaldehído , Sitios de Unión , Línea Celular , Humanos , Lipopolisacáridos/farmacología , Modelos Moleculares , Estructura Molecular , Conformación Proteica , Pirimidinas/farmacología , Relación Estructura-Actividad , Factor de Necrosis Tumoral alfa/química , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidoresRESUMEN
Novel substituted [5,5]-bicyclic pyrzazolones are presented as inhibitors of tumor necrosis factor-alpha (TNF-alpha) production. Many of these compounds show low nanomolar activity against lipopolysaccaride (LPS)-induced TNF-alpha production in THP-1 cells. This class of molecules was co-crystallized with mutated p38, and several analogs showed good oral bioavailability in the rat. Oral activity of these compounds in the rat iodoacetate model for osteoarthritis is discussed.
Asunto(s)
Pirazolonas/química , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Administración Oral , Animales , Disponibilidad Biológica , Lipopolisacáridos/farmacología , Modelos Moleculares , Pirazolonas/administración & dosificación , Pirazolonas/farmacocinética , Pirazolonas/farmacología , Ratas , Relación Estructura-Actividad , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
2-Aryl-3-pyrimidinyl based tumor necrosis factor-alpha (TNF-alpha) inhibitors, which contain a novel bicyclic pyrazolone core, are described. Many showed low-nanomolar activity against lipopolysaccharide-induced TNF-alpha production in monocytic cells. Secondary screening data are presented for the pyrimidinyl bicyclic pyrazolones. Several of these analogues showed good oral bioavailability in rat and efficacy in the rat iodoacetate in vivo model.