RESUMO
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.
Assuntos
Antibacterianos/síntese química , Proteínas de Transporte/química , Proteínas de Ciclo Celular/química , Proteínas de Escherichia coli/química , Indóis/síntese química , Piperidinas/síntese química , Antibacterianos/farmacologia , Divisão Celular/efeitos dos fármacos , Técnicas de Química Combinatória , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Indóis/farmacologia , Concentração Inibidora 50 , Piperidinas/farmacologia , Ligação Proteica/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
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.
Assuntos
Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/metabolismo , Desenho de Fármacos , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/metabolismo , Indóis/síntese química , Quinazolinas/síntese química , Sequência de Aminoácidos , Indóis/química , Indóis/metabolismo , Dados de Sequência Molecular , Ligação Proteica/fisiologia , Quinazolinas/química , Quinazolinas/metabolismoRESUMO
A chemically generated mutant of Staphylococcus aureus RN4220, GC6668, was isolated that had a fourfold increase in resistance to vancomycin. This phenotype reverted back to susceptibility by insertional mutagenesis with Tn917. In a selected set of revertants, Tn917 insertion was mapped to a unique chromosomal region upstream of mprF, a recently described gene that determines staphylococcal resistance to several host defense peptides. The genetic linkage between the vancomycin susceptibility and Tn917 insertion was then confirmed by transduction backcrosses into both GC6668 and GISA isolates, MER-S12 and HT2002 0127. Northern blot analysis, insertional inactivation and complementation experiments showed that mprF mediates vancomycin susceptibility in S. aureus. The inactivation of mprF by Tn917 insertion in HT2002 0127 caused a significant increase in the binding of vancomycin to the cell membranes. This observation serves as a likely mechanism of the increased vancomycin susceptibility associated with mprF inactivation.
Assuntos
Proteínas de Bactérias/genética , Staphylococcus aureus/efeitos dos fármacos , Resistência a Vancomicina/genética , Aminoaciltransferases , Proteínas de Bactérias/fisiologia , Elementos de DNA Transponíveis , Testes de Sensibilidade Microbiana , Mutagênese InsercionalRESUMO
A cohort of 56 patients infected with related strains of Mycobacterium tuberculosis, the S75 group, was identified in a New Jersey population-based study of all isolates with a low number of copies of the insertion element IS6110. Genotyping was combined with surveillance data to identify the S75 group and to elucidate its recent evolution. The S75 group had similar demographic and geographic characteristics. Seventeen persons (30%) were linked epidemiologically. The S75 group was segregated from other low-copy-number isolates on the basis of several independent molecular methods. This group included 3 IS6110 genotype variants: BE, H6, and C28, containing 1, 2, and 3 IS6110 insertions, respectively. IS6110 insertion site mapping and comparative sequence analysis strongly suggest a stepwise acquisition of IS6110 elements from BE to H6 to C28. S75 represents a locally produced strain cluster that has recently evolved. The combination of multiple molecular tools with traditional epidemiology provides novel insights into dissemination, local transmission, and evolution of M. tuberculosis.
