RESUMO
Lipid II analogues bearing major modifications on the second sugar (GlcNAc) were synthesized and evaluated for their substrate activity toward TGases. Unexpectedly, N-deacetyled lipid II decreased its activity dramatically, and the C4-axial OH lipid II became an inhibitor (IC50 = 8 µM) with an approximately 14-fold increase in binding affinity toward TGase (25 vs. 27).
Assuntos
Clostridioides difficile/enzimologia , Inibidores Enzimáticos/farmacologia , Escherichia coli/enzimologia , Lipídeos/farmacologia , Peptidoglicano Glicosiltransferase/antagonistas & inibidores , Açúcares/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Lipídeos/química , Peptidoglicano Glicosiltransferase/metabolismo , Relação Estrutura-Atividade , Especificidade por Substrato , Açúcares/síntese química , Açúcares/químicaRESUMO
Systematic structural modifications of the muramic acid, peptide, and nucleotide moieties of Park's nucleotide were performed to investigate the substrate specificity of B. subtilis MraY (MraYBS). It was found that the simplest analogue of Park's nucleotide only bearing the first two amino acids, l-alanine-iso-d-glutamic acid, could function as a MraYBS substrate. Also, the acid group attached to the Cα of iso-d-glutamic acid was found to play an important role for substrate activity. Epimerization of the C4-hydroxyl group of muramic acid and modification at the 5-position of the uracil in Park's nucleotide were both found to dramatically impair their substrate activity. Unexpectedly, structural modifications on the uracil moiety changed the parent molecule from a substrate to an inhibitor, blocking the MraYBS translocation. One unoptimized inhibitor was found to have a Ki value of 4 ± 1 µM against MraYBS, more potent than tunicamycins.
Assuntos
Proteínas de Bactérias/metabolismo , Nucleotídeos/metabolismo , Transferases/metabolismo , Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Testes de Sensibilidade Microbiana , Conformação de Ácido Nucleico , Nucleotídeos/química , Staphylococcus aureus/efeitos dos fármacos , Especificidade por Substrato , Transferases/antagonistas & inibidores , Transferases/química , Transferases (Outros Grupos de Fosfato Substituídos)RESUMO
Preparation of Lipidâ II analogues containing an enzymatically uncleavable 1-C-glycoside linkage between the disaccharide moiety and the pyrophosphate- or pyrophosphonate-lipid moiety is described. The synthesis of a common 1-C-vinyl disaccharide intermediate has been developed that allows easy preparation of both an elongated sugar-phosphate bond and a sugar-phosphonate moiety, which are coupled with the polyprenyl phosphate to give the desired molecules. Inhibition studies show how a subtle structural modification results in dramatically different potency toward bacterial transglycosylase (TGase), and the results identify Lipidâ II-C-O-PP (IC50 =25 µM) as a potential TGase inhibitor.
