RESUMO
In the peptidoglycan of Mycobacterium leprae, L-alanine of the side chain is replaced by glycine. When expressed in Escherichia coli, MurC (UDP-N-acetyl-muramate:L-alanine ligase) of M. leprae showed K(m) and V(max) for L-alanine and glycine similar to those of Mycobacterium tuberculosis MurC, suggesting that another explanation should be sought for the presence of glycine.
Assuntos
Alanina/metabolismo , Glicina/metabolismo , Mycobacterium leprae/enzimologia , Mycobacterium tuberculosis/enzimologia , Peptídeo Sintases/metabolismo , Transferases , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Clonagem Molecular , Escherichia coli/genética , Expressão Gênica , Genes Bacterianos , Dados de Sequência Molecular , Família Multigênica , Mycobacterium leprae/genética , Mycobacterium tuberculosis/genética , Peptídeo Sintases/genética , Peptídeo Sintases/isolamento & purificação , Homologia de Sequência de Aminoácidos , Transferases (Outros Grupos de Fosfato Substituídos)RESUMO
The ponA gene of Mycobacterium smegmatis encodes a 95-kDa penicillin binding protein, PBP1, that is similar to PBP1s of Mycobacterium tuberculosis and Mycobacterium leprae. Transposon disruption of ponA in M. smegmatis resulted in a PBP1-deficient mutant that was sensitive to beta-lactam antibiotics, was more permeable to glycine, and grew slowly in liquid culture.
Assuntos
Proteínas de Bactérias , Proteínas de Transporte/genética , Muramilpentapeptídeo Carboxipeptidase/genética , Mutação/genética , Mycobacterium smegmatis/genética , Permeabilidade da Membrana Celular/genética , Meios de Cultura , Glicina/metabolismo , Hexosiltransferases/genética , Hexosiltransferases/metabolismo , Cinética , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , Mycobacterium smegmatis/enzimologia , Mycobacterium smegmatis/crescimento & desenvolvimento , Proteínas de Ligação às Penicilinas , Peptidil Transferases/genética , Peptidil Transferases/metabolismo , Reação em Cadeia da Polimerase , beta-Lactamases/genética , beta-Lactamases/metabolismoRESUMO
Calmodulin-like protein has been established as the primary receptor for calcium in eukaryotic as well as prokaryotic cells. The calmodulin-calcium complex regulates a variety of enzymes including nucleotide phosphodiesterase. Recently, the presence of this protein in Mycobacterium leprae has been demonstrated and the effects of phenothiazine-type calmodulin antagonists on in vitro growth of M. leprae in a cell-free culture system were investigated. Two biochemical parameters were used to measure metabolic activity and growth of the organism. Among the six phenothiazine derivatives tested, trifluoperazine appeared to be the most potent in inhibiting the in vitro growth of M. leprae, with an MIC of 10 micrograms/ml. Chlorpromazine, triflupromazine and thioridazine were less active than trifluoperazine, with an MIC of 20 micrograms/ml each, while the other two, acetopromazine and fluphenazine, were totally ineffective even at 80 micrograms/ml. All four compounds inhibited the uptake of labelled acetate, glycine and thymidine by whole cells of M. leprae. This suggests that these phenothiazine derivatives have multiple sites of action and probably affect the synthesis of lipids, proteins and DNA.
Assuntos
Antipsicóticos/farmacologia , Calmodulina/antagonistas & inibidores , Mycobacterium leprae/efeitos dos fármacos , Mycobacterium leprae/metabolismo , Acepromazina/farmacologia , Acetatos/metabolismo , Clorpromazina/farmacologia , Glicina/metabolismo , Testes de Sensibilidade Microbiana , Mycobacterium leprae/citologia , Tioridazina/farmacologia , Timidina/metabolismo , Trifluoperazina/farmacologiaRESUMO
The radiometric method has been applied for studying the metabolism of M. lepraemurium and the conditions which might force or inhibit its metabolic activity in vitro. These organisms assimilate and oxidize (U-14C) glycerol, and (U-14C) acetate, but are unable to oxidize (U-14C) glucose, (U-14C) pyruvate, (U-14C) glycine and 14C-formate. When incubated at 30 degrees C M. lepraemurium oxidizes (U-14C) acetate to 14CO2 faster than 37 degrees C. The smae effect was observed with increasing concentrations of polysorbate 80 (Tween 80), or the 14C-substrate. No change in metabolic rate was observed when the organisms were kept at -20 degrees C for 12 days. Although tried several times, it was not possible to demonstrate any "inhibitors" of bacterial metabolism in the reaction system. The radiometric method seems to be an important tool for studying metabolic pathways and the influence of physical and biochemical factors on the metabolism of M. lepraemurium in vitro.