RESUMO
The gcpE gene product controls one of the terminal steps of isoprenoid biosynthesis via the mevalonate independent 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway. This pathway is utilized by a variety of eubacteria, the plastids of algae and higher plants, and the plastid-like organelle of malaria parasites. Recombinant GcpE protein from the hyperthermophilic bacterium Thermus thermophilus was produced in Escherichia coli and purified under dioxygen-free conditions. The protein was enzymatically active in converting 2-C-methyl-D-erythritol-2,4-cyclodiphosphate (MEcPP) into (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) in the presence of dithionite as reductant. The maximal specific activity was 0.6 micromol x min(-1) x mg(-1) at pH 7.5 and 55 degrees C. The kcat value was 0.4 s(-1) and the K(m) value for HMBPP 0.42 mM.
Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Enzimas , Fosfatos de Poli-Isoprenil/biossíntese , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Escherichia coli/metabolismo , Cinética , Luz , Ativação Linfocitária , Modelos Químicos , Dados de Sequência Molecular , Organofosfatos/farmacologia , Oxigênio/metabolismo , Plasmídeos/metabolismo , Plastídeos/metabolismo , Pirimidinas/farmacologia , Proteínas Recombinantes/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Linfócitos T/metabolismo , Thermus thermophilus/metabolismo , Raios UltravioletaRESUMO
In view of the promising antimalarial activity of fosmidomycin or its N-acetyl homologue FR900098, the objective of this work was to investigate the influence of aromatic substituents in the alpha-position of the phosphonate moiety. The envisaged analogues were prepared using a linear route involving a 3-aryl-3-phosphoryl propanal intermediate. The activities of all compounds were evaluated on Eschericia coli 1-deoxy-d-xylulose 5-phosphate reductoisomerase and against two Plasmodium falciparum strains. Compared with fosmidomycin, several analogues displayed enhanced activity towards the P. falciparum strains. Compound 1e with a 3,4-dichlorophenyl substitution in the alpha-position of fosmidomycin emerged as the most potent analogue of this series. It is approximately three times more potent in inhibiting the growth of P. falciparum than FR900098, the most potent representative of this class reported so far.
Assuntos
Antimaláricos/síntese química , Fosfomicina/análogos & derivados , Plasmodium falciparum/efeitos dos fármacos , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Fosfomicina/síntese química , Fosfomicina/química , Fosfomicina/farmacologia , Plasmodium falciparum/crescimento & desenvolvimentoRESUMO
FR900098 represents a derivative of the new antimalarial drug fosmidomycin with enhanced activity. The mechanism of action is the inhibition of the 1-desoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase, an essential enzyme of the mevalonate independent pathway of isoprenoid biosynthesis. Prodrugs with increased oral activity in mice infected with the rodent malaria parasite Plasmodium vinckei were obtained by masking the phosphonate moiety of FR900098 as alkoxycarbonyloxyethyl esters.
Assuntos
Antimaláricos/uso terapêutico , Fosfomicina/análogos & derivados , Malária/prevenção & controle , Pró-Fármacos/uso terapêutico , Administração Oral , Aldose-Cetose Isomerases/antagonistas & inibidores , Aldose-Cetose Isomerases/metabolismo , Animais , Antimaláricos/síntese química , Antimaláricos/farmacocinética , Disponibilidade Biológica , Relação Dose-Resposta a Droga , Fosfomicina/sangue , Fosfomicina/síntese química , Fosfomicina/farmacocinética , Fosfomicina/uso terapêutico , Malária/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , Oxirredutases/antagonistas & inibidores , Oxirredutases/metabolismo , Plasmodium/efeitos dos fármacos , Pró-Fármacos/síntese química , Pró-Fármacos/farmacocinética , Relação Quantitativa Estrutura-AtividadeRESUMO
FR900098 represents an improved derivative of the new antimalarial drug fosmidomycin and acts through inhibition of the 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase, an essential enzyme of the mevalonate independent pathway of isoprenoid biosynthesis. Prodrugs with increased activity after oral administration were obtained by chemical modification of the phosphonate moiety to yield acyloxyalkyl esters. The most successful compound demonstrated 2-fold increased activity in mice infected with the rodent malaria parasite Plasmodium vinckei.
Assuntos
Antimaláricos/síntese química , Antimaláricos/farmacologia , Fosfomicina/análogos & derivados , Fosfomicina/síntese química , Fosfomicina/farmacologia , Pró-Fármacos/síntese química , Pró-Fármacos/farmacologia , Animais , Antimaláricos/farmacocinética , Disponibilidade Biológica , Fosfomicina/farmacocinética , Indicadores e Reagentes , Lisofosfolipídeos/metabolismo , Malária/tratamento farmacológico , Malária/parasitologia , Ácido Mevalônico/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Pró-Fármacos/farmacocinéticaRESUMO
Fosmidomycin acts through inhibition of 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase, a key enzyme of the nonmevalonate pathway of isoprenoid biosynthesis. It possesses potent antimalarial activity in vitro and in murine malaria. In a recent clinical study, fosmidomycin was effective and well tolerated in the treatment of patients with acute uncomplicated Plasmodium falciparum malaria but resulted in an unacceptably high rate of recrudescence. In order to identify a potential combination partner, the interaction of fosmidomycin with a number of antimalarial drugs in current use was investigated in a series of in vitro experiments. Synergy was observed between fosmidomycin and the lincosamides, lincomycin and clindamycin. The efficacy of a combination of fosmidomycin and clindamycin was subsequently demonstrated in the Plasmodium vinckei mouse model.