Structural basis for specific inhibition of salicylate synthase from Mycobacterium abscessus

Blocking iron uptake and metabolism has been emerging as a promising therapeutic strategy for the development of novel antimicrobial compounds. Like all mycobacteria, M. abscessus (Mab) has evolved several countermeasures to scavenge iron from host carrier proteins, including the production of siderophores, which play a crucial role in these processes. In this study, we solved, for the first time, the crystal structure of Mab-SaS, the first enzyme involved in the biosynthesis of siderophores. Moreover, we screened a small, focused library and identified a compound exhibiting a potent inhibitory effect against Mab-SaS (IC50 ≈ 2 μM). Its binding mode was investigated by means of Induced Fit Docking simulations, performed on the crystal structure presented herein. Furthermore, cytotoxicity data and pharmacokinetic predictions revealed the safety and drug-likeness of this class of compounds. Finally, the crystallographic data were used to optimize the model for future virtual screening campaigns. Taken together, the findings of our study pave the way for the identification of potent Mab-SaS inhibitors, based on both established and unexplored chemotypes.

Eco-Friendly Bio-Based Solvents for the Acetylation of the Amino Group of Amino Acids

Nature-derived products, like juices and peel extracts of fruits and vegetables, have emerged in recent years as interesting and sustainable alternatives to traditional solvents in several synthetic applications. Herein, we present a green and fast method for the N-acetylation of amino acids, using several bio-based solvents (vinegar, tomato/kiwi/apple peel extracts, lemon juice, etc.). The high reactivity of the amino group is often a limitation in synthetic processes, making its protection a necessary step to achieve pure products and limit side reactions. Therefore, versatile, time-efficient procedures, minimal purification efforts, and good yields are desirable features for these transformations. Our new method meets all these criteria, offering a valuable and eco-friendly alternative to traditional approaches. In detail, we managed to obtain comparable yields to established setups, while improving safety and reducing the environmental impact of the overall process. Most notably, the milder conditions made it possible to avoid the use of running water (saving about 250 L/reaction) and electric-powered cooling devices.

cAMP effects in neuroendocrine tumors: The role of Epac and PKA in cell proliferation and adhesion

cAMP effects have been initially attributed to protein kinase A (PKA) activation. Subsequently, two exchange proteins directly activated by cAMP (Epac1/2) have been identified as cAMP targets. Aim of this study was to investigate cAMP effects in pancreatic-NET (P-NET) and bronchial carcinoids and in corresponding cell lines (QGP-1 and H727) on cell proliferation and adhesion and to determine PKA and Epac role in mediating these effects. We found that cAMP increased cyclin D1 expression in P-NET and QGP-1 cells, whereas it had opposite effects on bronchial carcinoids and H727 cells and it promoted cell adhesion in QGP-1 and H727 cells. These effects are mimicked by Epac and PKA specific analogs, activating the small GTPase Rap1. In conclusion, we demonstrated that cAMP exerted divergent effects on proliferation and promoted cell adhesion of different neuroendocrine cell types, these effects being mediated by both Epac and PKA and involving the same effector GTPase Rap1.