RESUMO
Resistance of bacterial pathogens against antibiotics is declared by WHO as a major global health threat. As novel antibacterial agents are urgently needed, we re-assessed the broad-spectrum myxobacterial antibiotic myxovalargin and found it to be extremely potent against Mycobacterium tuberculosis. To ensure compound supply for further development, we studied myxovalargin biosynthesis in detail enabling production via fermentation of a native producer. Feeding experiments as well as functional genomics analysis suggested a structural revision, which was eventually corroborated by the development of a concise total synthesis. The ribosome was identified as the molecular target based on resistant mutant sequencing, and a cryo-EM structure revealed that myxovalargin binds within and completely occludes the exit tunnel, consistent with a mode of action to arrest translation during a late stage of translation initiation. These studies open avenues for structure-based scaffold improvement toward development as an antibacterial agent.
Assuntos
Mycobacterium tuberculosis , Myxococcales , Antibacterianos/química , Ribossomos/metabolismo , Biossíntese de ProteínasRESUMO
The oxidative oligoazidation of phenols and ketones using iodine azide (IN3) provided by its release from an ion exchange resin is reported. Preliminary mechanistic studies indicate a previously unknown reactivity of iodine azide toward phenols and ketones.
RESUMO
Chemical probes that covalently modify cysteine residues in a protein-specific manner are valuable tools for biological investigations. Covalent fragments are increasingly implemented as probe starting points, but the complex relationship between fragment structure and binding kinetics makes covalent fragment optimization uniquely challenging. We describe a new technique in covalent probe discovery that enables data-driven optimization of covalent fragment potency and selectivity. This platform extends beyond the existing repertoire of methods for identifying covalent fragment hits by facilitating rapid multiparameter kinetic analysis of covalent structure-activity relationships through the simultaneous determination of Ki , kinact and intrinsic reactivity. By applying this approach to develop novel probes against electrophile-sensitive kinases, we showcase the utility of the platform in hit identification and highlight how multiparameter kinetic analysis enabled a successful fragment-merging strategy.
Assuntos
Acrilamida/farmacologia , Cisteína/farmacologia , Corantes Fluorescentes/farmacologia , Fosfotransferases/antagonistas & inibidores , Acrilamida/química , Cristalografia por Raios X , Cisteína/química , Corantes Fluorescentes/química , Humanos , Cinética , Modelos Moleculares , Estrutura Molecular , Fosfotransferases/metabolismo , Relação Estrutura-Atividade , TermodinâmicaRESUMO
This report discloses the photochemical homolytic cleavage of iodine azide after its formation following release from polymer-bound bisazido iodate(I) anions. A series of radical reactions are reported including the 1,2-functionlization of alkenes and the unprecedented chemoselective oxidation of secondary alcohols in the presence of primary alcohols.