Test

The synthesis and identification of sulfonamido-aryl ethers as potent bradykinin B1 receptor antagonists from a $60,000 member encoded combinatorial library are reported. Two distinct series of compounds exhibiting different structure-activity relationships were identified in a bradykinin B1 whole-cell receptor-binding assay. Specific examples exhibit K i values of $10 nM.

Candidate antibacterials are usually identifi ed on the basis of their in vitro activity. However, the apparent inhibitory activity of new leads can be misleading because most culture media do not reproduce an environment relevant to infection in vivo . In this study, while screening for novel anti-tuberculars, we uncovered how carbon metabolism can affect antimicrobial activity. Novel pyrimidine -imidazoles (PIs) were identifi ed in a whole-cell screen against Mycobacterium tuberculosis . Lead optimization generated in vitro potent derivatives with desirable pharmacokinetic properties, yet without in vivo effi cacy. Mechanism of action studies linked the PI activity to glycerol metabolism, which is not relevant for M. tuberculosis during infection. PIs induced self-poisoning of M. tuberculosis by promoting the accumulation of glycerol phosphate and rapid ATP depletion. This study underlines the importance of understanding central bacterial metabolism in vivo and of developing predictive in vitro culture conditions as a prerequisite for the rational discovery of new antibiotics.

Regulated proteolysis by the two-component NS2B/ NS3 protease of dengue virus is essential for virus replication and the maturation of infectious virions. The functional similarity between the NS2B/NS3 proteases from the four genetically and antigenically distinct serotypes was addressed by characterizing the differences in their substrate specificity using tetrapeptide and octapeptide libraries in a positional scanning format, each containing 130,321 substrates. The proteases from different serotypes were shown to be functionally homologous based on the similarity of their substrate cleavage preferences. A strong preference for basic amino acid residues (Arg/Lys) at the P1 positions was observed, whereas the preferences for the P2-4 sites were in the order of Arg > Thr > Gln/Asn/Lys for P2, Lys > Arg > Asn for P3, and Nle > Leu > Lys > Xaa for P4. The prime site substrate specificity was for small and polar amino acids in P1 and P3. In contrast, the P2 and P4 substrate positions showed minimal activity. The influence of the P2 and P3 amino acids on ground state binding and the P4 position for transition state stabilization was identified through single substrate kinetics with optimal and suboptimal substrate sequences. The specificities observed for dengue NS2B/NS3 have features in common with the physiological cleavage sites in the dengue polyprotein; however, all sites reveal previously unrecognized suboptimal sequences.