Small molecule inhibitors of anthrax edema factor

Emerging and Re-emerging Warheads for Targeted Covalent Inhibitors: An Update

Covalent inhibitors and other types of covalent modalities have seen a revival in the past two decades, with a variety of new targeted covalent drugs having been approved in recent years. A key feature of such molecules is an intrinsically reactive group, typically a weak electrophile, which enables the irreversible or reversible formation of a covalent bond with a specific amino acid of the target protein. This reactive group, often called the "warhead", is a critical determinant of the ligand's activity, selectivity, and general biological properties. In 2019, we summarized emerging and re-emerging warhead chemistries to target cysteine and other amino acids (Gehringer, M.; Laufer, S. A. J. Med. Chem. 2019, 62, 5673-5724; DOI: 10.1021/acs.jmedchem.8b01153). Since then, the field has rapidly evolved. Here we discuss the progress on covalent warheads made since our last Perspective and their application in medicinal chemistry and chemical biology.

Chemoselective Reactions of Functionalized Sulfonyl Halides

Chemoselective transformations of functionalized sulfonyl fluorides and chlorides are surveyed comprehensively. It is shown that sulfonyl fluorides provide an excellent selectivity control in their reactions. Thus, numerous conditions are tolerated by the SO2 F group - from amide and ester formation to directed ortho-lithiation and transition-metal-catalyzed cross-couplings. Meanwhile, sulfur (VI) fluoride exchange (SuFEx) is also compatible with numerous functional groups, thus confirming its title of "another click reaction". On the contrary, with a few exceptions, most transformations of functionalized sulfonyl chlorides typically occur at the SO2 Cl moiety.

Acyclic nucleoside phosphonates with 2-aminothiazole base as inhibitors of bacterial and mammalian adenylate cyclases

A series of novel acyclic nucleoside phosphonates (ANPs) was synthesized as potential adenylate cyclase inhibitors, where the adenine nucleobase of adefovir (PMEA) was replaced with a 5-substituted 2-aminothiazole moiety. The design was based on the structure of MB05032, a potent and selective inhibitor of fructose 1,6-bisphosphatase and a good mimic of adenosine monophosphate (AMP). From the series of eighteen novel ANPs, which were prepared as phosphoroamidate prodrugs, fourteen compounds were potent (single digit micromolar or submicromolar) inhibitors of Bordetella pertussis adenylate cyclase toxin (ACT), mostly without observed cytotoxicity in J774A.1 macrophage cells. Selected phosphono diphosphates (nucleoside triphosphate analogues) were potent inhibitors of ACT (IC50 as low as 37 nM) and B. anthracis edema factor (IC50 as low as 235 nM) in enzymatic assays. Furthermore, several ANPs were found to be selective mammalian AC1 inhibitors in HEK293 cell-based assays (although with some associated cytotoxicity) and one compound exhibited selective inhibition of mammalian AC2 (only 12% of remaining adenylate cyclase activity) but no observed cytotoxicity. The mammalian AC1 inhibitors may represent potential leads in development of agents for treatment of human inflammatory and neuropathic pain.

Structural Biology and Molecular Modeling to Analyze the Entry of Bacterial Toxins and Virulence Factors into Host Cells

Understanding the functions and mechanisms of biological systems is an outstanding challenge. One way to overcome it is to combine together several approaches such as molecular modeling and experimental structural biology techniques. Indeed, the interplay between structural and dynamical properties of the system is crucial to unravel the function of molecular machinery’s. In this review, we focus on how molecular simulations along with structural information can aid in interpreting biological data. Here, we examine two different cases: (i) the endosomal translocation toxins (diphtheria, tetanus, botulinum toxins) and (ii) the activation of adenylyl cyclase inside the cytoplasm (edema factor, CyA, ExoY).