RESUMO
A series of derivatives of the antimycobacterial natural product pyridomycin have been prepared with the C2 side chain attached to the macrocyclic core structure by a C-C single bond, in place of the synthetically more demanding enol ester double bond found in the natural product. Hydrophobic C2 substituents of sufficient size generally provide for potent anti-Mtb activity of these dihydropyridomycins (minimum inhibitory concentration (MIC) values around 2.5 µM), with several analogs thus approaching the activity of natural pyridomycin. Surprisingly, some of these compounds, in contrast to pyridomycin, are insensitive to overexpression of InhA in Mycobacterium tuberculosis (Mtb). This indicates that their anti-Mtb activity does not critically depend on the inhibition of InhA and that their overall mode of action may differ from that of the original natural product lead.
Assuntos
Antituberculosos/farmacologia , Inibidores Enzimáticos/farmacologia , Oligopeptídeos/farmacologia , Antituberculosos/síntese química , Antituberculosos/química , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Oligopeptídeos/síntese química , Oligopeptídeos/química , Oxirredutases/antagonistas & inibidores , Relação Estrutura-AtividadeRESUMO
Pyridomycin, a natural product with potent antituberculosis activity, inhibits a major drug target, the InhA enoyl reductase. Here, we unveil the co-crystal structure and unique ability of pyridomycin to block both the NADH cofactor- and lipid substrate-binding pockets of InhA. This is to our knowledge a first-of-a-kind binding mode that discloses a new means of InhA inhibition. Proof-of-principle studies show how structure-assisted drug design can improve the activity of new pyridomycin derivatives.
Assuntos
Antituberculosos/química , Proteínas de Bactérias/química , NAD/química , Oligopeptídeos/química , Oxirredutases/química , Sítios de Ligação , Cristalografia por Raios X , Modelos Moleculares , Especificidade por SubstratoRESUMO
Dihydropyridomycins 2 and 3, which lack the characteristic enol ester moiety of the potent antimycobacterial natural product pyridomycin (1), have been prepared from l-Thr, R- and S-hydroxy isovaleric acid, and 3-pyridinecarboxaldehyde. The 2R isomer 2 shows only 4-fold lower anti-Mtb activity than 1, indicating that the enol ester moiety in the natural product is not critical for its biological activity. This finding establishes 2 as a potent and more practical lead for anti-TB drug discovery.
