Mechanism of action of a novel series of naphthyridine-type ribosome inhibitors: enhancement of tRNA footprinting at the decoding site of 16S rRNA.

The novel ribosome inhibitors (NRIs) are a broad-spectrum naphthyridine class that selectively inhibits bacterial protein synthesis (P. J. Dandliker et al.

Chiral DNA gyrase inhibitors. 3. Probing the chiral preference of the active site of DNA gyrase. Synthesis of 10-fluoro-6-methyl-6,7-dihydro-9-piperazinyl- 2H-benzo[a]quinolizin-20-one-3-carboxylic acid analogues.

In pursuit of an apparent literature anomaly, S- and R-6-methyl-6,7-dihydro-2H-benzo[a]quinolizin-2-one-3-carboxylic acids (12 and 22) were synthesized by an unambiguous route from optically active norephedrines, and their antibacterial potencies were measured. Against Gram-negative microorganisms and DNA gyrase a preference for S-absolute configuration was found whereas R-absolute stereochemistry was more active against Gram-positives. These results are in partial conflict with an earlier report.

Novel antibacterial class.

We report the discovery and characterization of a novel ribosome inhibitor (NRI) class that exhibits selective and broad-spectrum antibacterial activity. Compounds in this class inhibit growth of many gram-positive and gram-negative bacteria, including the common respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis, and are nontoxic to human cell lines. The first NRI was discovered in a high-throughput screen designed to identify inhibitors of cell-free translation in extracts from S.

In vitro antibacterial potency and spectrum of ABT-492, a new fluoroquinolone.

ABT-492 demonstrated potent antibacterial activity against most quinolone-susceptible pathogens. The rank order of potency was ABT-492 > trovafloxacin > levofloxacin > ciprofloxacin against quinolone-susceptible staphylococci, streptococci, and enterococci. ABT-492 had activity comparable to those of trovafloxacin, levofloxacin, and ciprofloxacin against seven species of quinolone-susceptible members of the family Enterobacteriaceae, although it was less active than the comparators against Citrobacter freundii and Serratia marcescens.

DNA sequence specificity for topoisomerase II poisoning by the quinoxaline anticancer drugs XK469 and CQS.

The two known antineoplastic quinoxaline topoisomerase II poisons, XK469 (NSC 697887) and CQS (chloroquinoxaline sulfonamide, NSC 339004), were compared for DNA cleavage site specificity, using purified human topoisomerase IIalpha and human topoisomerase IIbeta. The DNA cleavage intensity pattern for topoisomerase IIalpha poisoning by CQS closely resembled that of VM-26, despite the lack of any apparent common pharmacophore. In contrast, the topoisomerase IIalpha DNA cleavage intensity patterns of XK469 and CQS were very different from one another despite the similar overall structures of the two drugs.