RESUMEN
ZipA is a membrane anchored protein in Escherichia coli that interacts with FtsZ, a homolog of eukaryotic tubulins, forming a septal ring structure that mediates bacterial cell division. Thus, the ZipA/FtsZ protein-protein interaction is a potential target for an antibacterial agent. We report here an NMR-based fragment screening approach which identified several hits that bind to the C-terminal region of ZipA. The screen was performed by 1H-15N HSQC experiments on a library of 825 fragments that are small, lead-like, and highly soluble. Seven hits were identified, and the binding mode of the best one was revealed in the X-ray crystal structure. Similar to the ZipA/FtsZ contacts, the driving force in the binding of the small molecule ligands to ZipA is achieved through hydrophobic interactions. Analogs of this hit were also evaluated by NMR and X-ray crystal structures of these analogs with ZipA were obtained, providing structural information to help guide the medicinal chemistry efforts.
Asunto(s)
Antibacterianos/síntesis química , Proteínas Portadoras/antagonistas & inhibidores , Proteínas de Ciclo Celular/antagonistas & inhibidores , Evaluación Preclínica de Medicamentos/métodos , Proteínas de Escherichia coli/antagonistas & inhibidores , Espectroscopía de Resonancia Magnética , Complejos Multiproteicos/antagonistas & inhibidores , Antibacterianos/farmacología , Proteínas Portadoras/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cristalografía por Rayos X , Diseño de Fármacos , Proteínas de Escherichia coli/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Fragmentos de Péptidos/metabolismo , Unión Proteica , Relación Estructura-ActividadRESUMEN
The ZipA-FtsZ protein-protein interaction is a potential target for antibacterial therapy. The design and parallel synthesis of a combinatorial library of small molecules, which target the FtsZ binding area on ZipA are described. Compounds were demonstrated to bind to the FtsZ binding domain of ZipA by HSQC NMR and to inhibit cell division in a cell elongation assay.
Asunto(s)
Antibacterianos/síntesis química , Proteínas Portadoras/química , Proteínas de Ciclo Celular/química , Proteínas de Escherichia coli/química , Indoles/síntesis química , Piperidinas/síntesis química , Antibacterianos/farmacología , División Celular/efectos de los fármacos , Técnicas Químicas Combinatorias , Escherichia coli/citología , Escherichia coli/efectos de los fármacos , Indoles/farmacología , Concentración 50 Inhibidora , Piperidinas/farmacología , Unión Proteica/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
The binding of FtsZ to ZipA is a potential target for antibacterial therapy. Based on a small molecule inhibitor of the ZipA-FtsZ interaction, a parallel synthesis of small molecules was initiated which targeted a key region of ZipA involved in FtsZ binding. The X-ray crystal structure of one of these molecules complexed with ZipA was solved. The structure revealed an unexpected binding mode, facilitated by desolvation of a loosely bound surface water.
Asunto(s)
Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/metabolismo , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proteínas de Ciclo Celular/metabolismo , Diseño de Fármacos , Proteínas de Escherichia coli/antagonistas & inhibidores , Proteínas de Escherichia coli/metabolismo , Indoles/síntesis química , Quinazolinas/síntesis química , Secuencia de Aminoácidos , Indoles/química , Indoles/metabolismo , Datos de Secuencia Molecular , Unión Proteica/fisiología , Quinazolinas/química , Quinazolinas/metabolismoRESUMEN
D-optimal design and Projection to Latent Structures (PLS) analysis were used to optimize screening hit 5 (B. subtilis AcpS IC(50): 15 microM, B. subtilis MIC: >200 microM) into a series of 4H-oxazol-5-one, small molecule, antibacterial, AcpS inhibitors. Specifically, 15, 16 and 18 show microM or sub-microM AcpS inhibition (IC(50)s: 15: 1.1 microM, 16: 1.5 microM, 18: 0.27 microM) and moderate antibacterial activity (MICs: 12.5-50 microM) against B. subtilis, E. faecalis ATCC, E. faecalis VRE and S. pneumo+.