RESUMEN
A facile strategy is presented to enhance the accumulation of ferryl (iron(IV)-oxo) species in H2O2 dependent cytochrome P450s (CYPs) of the CYP152 family. We report the characterization of a highly chemoselective CYP decarboxylase from Staphylococcus aureus (OleTSA) that is soluble at high concentrations. Examination of OleTSA Compound I (CpdI) accumulation with a variety of fatty acid substrates reveals a dependence on resting spin-state equilibrium. Alteration of this equilibrium through targeted mutagenesis of the proximal pocket favors the high-spin form, and as a result, enhances Cpd-I accumulation to nearly stoichiometric yields.
Asunto(s)
Sistema Enzimático del Citocromo P-450 , Peróxido de Hidrógeno , Sistema Enzimático del Citocromo P-450/química , Ácidos Grasos/químicaRESUMEN
Novel bacterial topoisomerase inhibitors (NBTIs) are among the most promising new antibiotics in preclinical/clinical development. We previously reported dioxane-linked NBTIs with potent antistaphylococcal activity and reduced hERG inhibition, a key safety liability. Herein, polarity-focused optimization enabled the delineation of clear structure-property relationships for both microsomal metabolic stability and hERG inhibition, resulting in the identification of lead compound 79. This molecule demonstrates potent antibacterial activity against diverse Gram-positive pathogens, inhibition of both DNA gyrase and topoisomerase IV, a low frequency of resistance, a favorable in vitro cardiovascular safety profile, and in vivo efficacy in a murine model of methicillin-resistant Staphylococcus aureus infection.
Asunto(s)
Antibacterianos/farmacología , Dioxanos/farmacología , Inhibidores Enzimáticos/farmacología , Canales de Potasio Éter-A-Go-Go/antagonistas & inhibidores , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Girasa de ADN/metabolismo , Topoisomerasa de ADN IV/antagonistas & inhibidores , Topoisomerasa de ADN IV/metabolismo , Dioxanos/síntesis química , Dioxanos/química , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Canales de Potasio Éter-A-Go-Go/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Aza-peptide aldehydes and ketones are a new class of reversible protease inhibitors that are specific for the proteasome and clan CD cysteine proteases. We designed and synthesised aza-Leu derivatives that were specific for the chymotrypsin-like active site of the proteasome, aza-Asp derivatives that were effective inhibitors of caspases-3 and -6, and aza-Asn derivatives that inhibited S. mansoni and I. ricinus legumains. The crystal structure of caspase-3 in complex with our caspase-specific aza-peptide methyl ketone inhibitor with an aza-Asp residue at P1 revealed a covalent linkage between the inhibitor carbonyl carbon and the active site cysteinyl sulphur. Aza-peptide aldehydes and ketones showed no cross-reactivity towards cathepsin B or chymotrypsin. The initial in vitro selectivity of these inhibitors makes them suitable candidates for further development into therapeutic agents to potentially treat multiple myeloma, neurodegenerative diseases, and parasitic infections.
Asunto(s)
Aldehídos/farmacología , Compuestos Aza/farmacología , Diseño de Fármacos , Cetonas/farmacología , Péptidos/farmacología , Inhibidores de Proteasas/farmacología , Aldehídos/química , Animales , Compuestos Aza/química , Bovinos , Cristalografía por Rayos X , Cisteína Endopeptidasas/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Cetonas/química , Modelos Moleculares , Estructura Molecular , Péptidos/química , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/química , Complejo de la Endopetidasa Proteasomal/metabolismo , Relación Estructura-ActividadRESUMEN
Increasing levels of energy consumption, dwindling resources, and environmental considerations have served as compelling motivations to explore renewable alternatives to petroleum-based fuels, including enzymatic routes for hydrocarbon synthesis. Phylogenetically diverse species have long been recognized to produce hydrocarbons, but many of the enzymes responsible have been identified within the past decade. The enzymatic conversion of Cn chain length fatty aldehydes (or acids) to Cn-1 hydrocarbons, alkanes or alkenes, involves a C-C scission reaction. Surprisingly, the enzymes involved in hydrocarbon synthesis utilize non-heme mononuclear iron, dinuclear iron, and thiolate-ligated heme cofactors that are most often associated with monooxygenation reactions. In this review, we examine the mechanisms of several enzymes involved in hydrocarbon biosynthesis, with specific emphasis on the structural and electronic changes that enable this functional switch.