Development of improved inhibitors of wall teichoic acid biosynthesis with potent activity against Staphylococcus aureus

A small molecule (1835F03) that inhibits Staphylococcus aureus wall teichoic acid biosynthesis, a proposed antibiotic target, has been discovered. Rapid, parallel, solution-phase synthesis was employed to generate a focused library of analogs, providing detailed information about structure–activity relationships and leading to the identification of targocil, a potent antibiotic

Characterization of the 8-hydroxyquinoline scaffold for inhibitors of West Nile virus serine protease

West Nile virus (WNV) is a mosquito-borne member of flaviviruses that causes significant morbidity and mortality especially among children. There is currently no approved vaccine or antiviral therapeutic for human use. In a previous study, we described compounds containing the 8-hydroxyquinoline (8-HQ) scaffold as inhibitors of WNV serine protease (NS2B/NS3pro) in a high throughput screen (HTS) using the purified WNV NS2B/NS3pro as the target. In this study, we analyzed potencies of some commercially available as well as chemically synthesized derivatives of 8-HQ by biochemical assays. An insight into the contribution of various substitutions of 8-HQ moiety for inhibition of the protease activity was revealed. Most importantly, the substitution of the N1 of the 8-HQ ring by –CH– in compound 26 significantly reduced the inhibition of the viral protease by this naphthalen-1-ol derivative. The kinetic constant (Ki) for the most potent 8-HQ inhibitor (compound 14) with an IC50 value of 2.01 ± 0.08 ?M using the tetra-peptide substrate was determined to be 5.8 ?M. This compound inhibits the WNV NS2B/NS3pro by a competitive mode of inhibition which is supported by molecular modeling

Small-Molecule Inhibitors of Dengue-Virus Entry

Flavivirus envelope protein (E) mediates membrane fusion and viral entry from endosomes. A low-pH induced, dimer-to-trimer rearrangement and reconfiguration of the membrane-proximal “stem" of the E ectodomain draw together the viral and cellular membranes. We found stem-derived peptides from dengue virus (DV) bind stem-less E trimer and mimic the stem-reconfiguration step in the fusion pathway. We adapted this experiment as a high-throughput screen for small molecules that block peptide binding and thus may inhibit viral entry. A compound identified in this screen, 1662G07, and a number of its analogs reversibly inhibit DV infectivity. They do so by binding the prefusion, dimeric E on the virion surface, before adsorption to a cell. They also block viral fusion with liposomes. Structure-activity relationship studies have led to analogs with submicromolar IC90s against DV2, and certain analogs are active against DV serotypes 1,2, and 4. The compounds do not inhibit the closely related Kunjin virus. We propose that they bind in a previously identified, E-protein pocket, exposed on the virion surface and although this pocket is closed in the postfusion trimer, its mouth is fully accessible. Examination of the E-trimer coordinates (PDB 1OK8) shows that conformational fluctuations around the hinge could open the pocket without dissociating the trimer or otherwise generating molecular collisions. We propose that compounds such as 1662G07 trap the sE trimer in a “pocket-open" state, which has lost affinity for the stem peptide and cannot support the final “zipping up" of the stem

3D Animation using Visual Script Language

In animating virtual characters, it is necessary to provide an interface that allows users specify the characters' motion with high-level concepts as well as low-level details. And it will be convenient to user if the system provides an animation agent that processes various tasks for animation. In this paper, we suggest an agent (HUman-MOtion Agent: HUMOA) that controls behaviors and actions of virtual characters automatically. The agent is structured with multi-level and is operated according to semantics of scenario that is composed of events and visual scripts. Visual script is the gesture with mouse that describes characters' motion visually. The agent of multi-level structure has internal knowledge that is expressed as concepts and relations. So the agent can perform tasks of each level of abstraction automatically. A user can interact with virtual characters directly and intuitively using visual script language. And the agent of our system makes it easier to design animation sc..

Interaction of 1662G07 analogs with DI/DII.

<p>DI/DII was immobilized on a CM5 sensorchip. Analogs 3-148-1, 3-149-3, 3-149-14, 3-151-2, 3-151-2, 3-151-5, 3-151-4, 3-110-5, 3-110-14 and 3-110-22 were passed over the DI/DII surface at 10, 20 and 40 µM. Background for nonspecific binding to the chip surface was corrected for by passing the analogs over a protein-free channel. All measurements carried out in duplicate.</p

Reversibility of antiviral effect.

<p>Viral inocula were preincubated with 1662G07 analogs from the (A) 3-148 and 3-149 and (B) 3-110 series for 10′ at 37°C. DI/DII was then added in molar excess and the incubation continued for an additional 15′. Each inoculum was added to cells, and supernatants were harvested 24 hrs later. An inoculum preincubated with DI/DII alone at the same molar excess showed no loss in viral titre.</p

Biochemical, cytotoxicity and antiviral summary of selected compounds from the 3-110 series.

<p>Biochemical, cytotoxicity and antiviral summary of selected compounds from the 3-110 series.</p

Proposed mechanism of action of small-molecule inhibitors and postulated equilibrium between two conformations of the sE trimer.

<p>In the “pocket-open", inhibitor-stabilized conformation (right image), the stem-binding groove is absent and the final fusion-inducing step in the conformational change cannot occur. Moreover, sE in this pocket-open conformation would not bind stem-derived peptides. Domains I, II and III are in red, yellow and blue, respectively. All images created with PyMol.</p