Inhibition of and FtsZ Polymerization and Growth by Dihydroxynaphtyl Aryl Ketones.

The increasing detection of virulent and/or multidrug resistant bacterial strains makes necessary the development of new antimicrobial agents acting through novel mechanisms and cellular targets. A good choice are molecules aimed to interfere with the cell division machinery or , which is indispensable for bacterial survival and propagation. A key component of this machinery, and thus a good target, is FtsZ, a highly conserved GTPase protein that polymerizes in the middle of the cell on the inner face of the cytoplasmic membrane forming the Z ring, which acts as a scaffold for the recruitment of the proteins at the division site. In this work, we tested the inhibitory effect of five diaryl naphtyl ketone (dNAK) molecules on the polymerization of both and FtsZ (EcFtsZ and BsFtsZ, respectively). Among these compounds, dNAK 4 showed the strongest inhibition of FtsZ polymerization , with an IC of 2.3 ± 0.06 μM for EcFtsZ and 9.13 ± 0.66 μM for BsFtsZ. We found that dNAK 4 binds to GDP-FtsZ polymers but not to the monomer in GTP or GDP state. This led to the polymerization of short and curved filaments, rings, open rings forming clusters, and in the case of BsFtsZ, a novel cylindrical structure of stacked open rings. , dNAK 4 had almost no effect on the growth of in liquid culture, in contrast to the strong inhibitory effect observed over growth. The insensitivity of to this compound is probably related to the impermeability of dNAK 4 to the outer membrane. The low amount of this compound required to inhibit several of the bacterial strains tested and the lack of a cytotoxic effect at the concentrations used, makes dNAK 4 a very good candidate as a starting molecule for the development of a new antibiotic.