Targeting the ATG5-ATG16L1 Protein-Protein Interaction with a Hydrocarbon-Stapled Peptide Derived from ATG16L1 for Autophagy Inhibition.

Selective modulation of autophagy is a promising therapeutic strategy, especially for cancer treatment. However, the lack of specific autophagy inhibitors limits this strategy. The formation of the ATG12-ATG5-ATG16L1 complex is essential for targeting the ATG12-ATG5 conjugate to proper membranes and to generate LC3-II for the progression of autophagy. Thus, targeting ATG5-ATG16L1 protein-protein interactions (PPIs) might inhibit early stage autophagy with high specificity. In this paper, we report that a stapled peptide derived from ATG16L1 exhibits potent binding affinity to ATG5, striking resistance to proteolysis, and significant autophagy inhibition activities in cells.

Sacchathridine A, a prostaglandin release inhibitor from Saccharothrix sp.

Sacchathridine A (1) was isolated from the fermentation broth of strain Saccharothrix sp. MI559-46F5. The structure was determined as a new naphthoquinone derivative with an acetylhydrazino moiety by a combination of NMR, MS spectral analyses, and chemical degradation. Compound 1 showed inhibitory activity of prostaglandin E2 release in a concentration-dependent manner from human synovial sarcoma cells, SW982, with an IC50 value of 1.0 µM, but had no effect on cell growth up to 30 µM.

Inhibitors of human 2,3-oxidosqualene cyclase (OSC) discovered by virtual screening.

Five human 2,3-oxidosqualnene cyclase (OSC) inhibitors were discovered using the combination of a virtual screening based on a docking study and an isotope-free assay system. All of these inhibitors were revealed to have activities comparable or superior to that of LDAO, a known OSC inhibitor. The computational study of the newly identified inhibitors suggested that CH/π interactions with F444 and W581 contribute to the binding, and these interactions are candidates for additional structural filters in the next generation of virtual screening.

The synthesis of paleic acid, an antimicrobial agent effective against Mannheimia and Pasteurella, and its structurally related derivatives.

A synthetic route to paleic acid 1, antimicrobial agent effective against Mannheimia haemolytica and Pasteurella multocida, has been established. The absolute configuration of the secondary hydroxyl group was controlled by a catalytic asymmetric alkylation of an aldehyde using a chiral titanium sulfonamide complex and the cis double bond was installed using a Wittig reaction. This synthetic route was also applied to the preparation of structurally related analogs, which were used in structure-activity relationship studies for antibacterial activity.

Paleic acid, a fatty acid from Paenibacillus sp.: taxonomy, fermentation, isolation, structure determination, and anti-Mannheimia and -Pasteurella activity.

Paleic acid (1), an antibiotic, was obtained from a fermentation broth of Paenibacillus sp. BMK771-AF3. The compound is a fatty acid (9Z,16R)-16-hydroxy-9-octadecenoic acid ((R)-16-hydroxyoleic acid), whose isolation required protection of its polar functional groups. Mosher esters of paleic acid yielded information on the absolute configuration of secondary alcohol, and well-resolved (1)H NMR peaks around the double bond suggested that olefin adopted a Z geometry. Paleic acid showed potent antibacterial activity and narrow spectrum against Mannheimia haemolytica with MIC values ranging between 0.78 and 1.56 microg ml(-1).