Atromentin and leucomelone, the first inhibitors specific to enoyl-ACP reductase (FabK) of Streptococcus pneumoniae

Two potent inhibitors of FabK, the enoyl-acyl carrier protein (ACP) reductase of Streptococcus pneumoniae, were isolated from the solid state fermentation of an unidentified fungus F010248. Their structures were identified to be atromentin and leucomelone by various spectral analysis. Atromentin and leucomelone inhibited the FabK with IC50 values of 0.24 and 1.57 microM, respectively, while did not inhibit FabI, the enoyl-ACP reductase of either Escherichia coli or Staphylococcus aureus, even at 200 microM. Atromentin and leucomelone are the first inhibitors specific to the enoyl-ACP reductase (FabK) of Streptococcus pneumoniae.