Tuesday, August 31, 2021

A sulfonyl fluoride derivative inhibits EGFRL858R/T790M/C797S by covalent modification of the catalytic lysine

Francesca Ferlenghi, Laura Scalvini, Federica Vacondio, Riccardo Castelli, Nicole Bozza, Giuseppe Marseglia, Silvia Rivara, Alessio Lodola, Silvia La Monica, Roberta Minari, Pier Giorgio Petronini, Roberta Alfieri, Marcello Tiseo, Marco Mor,

European Journal of Medicinal Chemistry, 225, 2021, 113786,

https://doi.org/10.1016/j.ejmech.2021.113786

The emergence of the C797S mutation in EGFR is a frequent mechanism of resistance to osimertinib in the treatment of non-small cell lung cancer (NSCLC). In the present work, we report the design, synthesis and biochemical characterization of UPR1444 (compound 11), a new sulfonyl fluoride derivative which potently and irreversibly inhibits EGFRL858R/T790M/C797S through the formation of a sulfonamide bond with the catalytic residue Lys745. Enzymatic assays show that compound 11 displayed an inhibitory activity on EGFRWT comparable to that of osimertinib, and it resulted more selective than the sulfonyl fluoride probe XO44, recently reported to inhibit a significant part of the kinome. Neither compound 11 nor XO44 inhibited EGFRdel19/T790M/C797S triple mutant. When tested in Ba/F3 cells expressing EGFRL858R/T790M/C797S, compound 11 resulted significantly more potent than osimertinib at inhibiting both EGFR autophosphorylation and proliferation, even if the inhibition of EGFR autophosphorylation by compound 11 in Ba/F3 cells was not long lasting.



Sunday, August 29, 2021

A Potent Fluorescent Reversible-Covalent Inhibitor of Cardiac Muscle Contraction

 Fangze Cai, Thomas Kampourakis, Brittney A. Klein, and Brian D. Sykes

ACS Medicinal Chemistry Letters 2021
DOI: 10.1021/acsmedchemlett.1c00366

Compounds that directly modulate the response of the cardiac sarcomere have potential in the treatment of cardiac disease. While a number of sarcomere activators have been discovered and extensively studied, very few inhibitors have been identified. We report a potent cardiac sarcomere inhibitor, DN-F01, targeting the cardiac muscle thin filament protein troponin complex. Functional studies show that DN-F01 has a strong inhibitory calcium-dependent effect on cardiac myofibrillar ATPase activity with an IC50 value of 11 ± 4 nmol/L. DN-F01 is shown to bind to a cardiac troponin C–troponin I chimera (cChimera) with a KD of ∼50 nM using fluorescence spectroscopy, indicating that troponin is the likely target for DN-F01. NMR titrations of DN-F01 to C35S and A-Cys cChimera show covalent and noncovalent binding of DN-F01 bound to the calcium-saturated cChimera.



Monday, August 23, 2021

Activity-Based Hydrazine Probes for Protein Profiling of Electrophilic Functionality in Therapeutic Targets

Zongtao Lin, Xie Wang, Katelyn A. Bustin, Kyosuke Shishikura, Nate R. McKnight, Lin He, Radu M. Suciu, Kai Hu, Xian Han, Mina Ahmadi, Erika J. Olson, William H. Parsons, and Megan L. Matthews

ACS Central Science 2021

DOI: 10.1021/acscentsci.1c00616

Most known probes for activity-based protein profiling (ABPP) use electrophilic groups that tag a single type of nucleophilic amino acid to identify cases in which its hyper-reactivity underpins function. Much important biochemistry derives from electrophilic enzyme cofactors, transient intermediates, and labile regulatory modifications, but ABPP probes for such species are underdeveloped. Here, we describe a versatile class of probes for this less charted hemisphere of the proteome. The use of an electron-rich hydrazine as the common chemical modifier enables covalent targeting of multiple, pharmacologically important classes of enzymes bearing diverse organic and inorganic cofactors. Probe attachment occurs by both polar and radicaloid mechanisms, can be blocked by molecules that occupy the active sites, and depends on the proper poise of the active site for turnover. These traits will enable the probes to be used to identify specific inhibitors of individual members of these multiple enzyme classes, making them uniquely versatile among known ABPP probes.



Saturday, August 7, 2021

High-Throughput Crystallography Reveals Boron-Containing Inhibitors of a Penicillin-Binding Protein with Di- and Tricovalent Binding Modes

Hector Newman, Alen Krajnc, Dom Bellini, Charles J. Eyermann, Grant A. Boyle, Neil G. Paterson, Katherine E. McAuley, Robert Lesniak, Mukesh Gangar, Frank von Delft, Jürgen Brem, Kelly Chibale, Christopher J. Schofield, and Christopher G. Dowson

Journal of Medicinal Chemistry Article 2021

DOI: 10.1021/acs.jmedchem.1c00717

The effectiveness of β-lactam antibiotics is increasingly compromised by β-lactamases. Boron-containing inhibitors are potent serine-β-lactamase inhibitors, but the interactions of boron-based compounds with the penicillin-binding protein (PBP) β-lactam targets have not been extensively studied. We used high-throughput X-ray crystallography to explore reactions of a boron-containing fragment set with the Pseudomonas aeruginosa PBP3 (PaPBP3). Multiple crystal structures reveal that boronic acids react with PBPs to give tricovalently linked complexes bonded to Ser294, Ser349, and Lys484 of PaPBP3; benzoxaboroles react with PaPBP3 via reaction with two nucleophilic serines (Ser294 and Ser349) to give dicovalently linked complexes; and vaborbactam reacts to give a monocovalently linked complex. Modifications of the benzoxaborole scaffold resulted in a moderately potent inhibition of PaPBP3, though no antibacterial activity was observed. Overall, the results further evidence the potential for the development of new classes of boron-based antibiotics, which are not compromised by β-lactamase-driven resistance.



Thiol Reactivity of N-Aryl α-Methylene-γ-lactams: Influence of the Guaianolide Structure [@KayBrummond]

 Daniel P. Dempe, Chong-Lei Ji, Peng Liu, and Kay M. Brummond The Journal of Organic Chemistry, 2020 DOI: 10.1021/acs.joc.2c01530 The α-meth...