2-Nitrobenzyl Esters of Penam and Cephem Derivatives as Inhibitors of Penicillin-Binding Proteins

Nitroveratrole esters (i.e. 4,5-dimethoxy-2-nitrobenzyl (NV) esters) of penicillin and cephalosporin derivatives have been prepared in the course of a program dedicated to photosensitive protein microarrays. Surprisingly, some molecules revealed to be acylating inhibitors of R39 and BlaR-CTD proteins (two representative Penicillin Binding Proteins (PBPs)), while being bad substrates of beta-lactamases (bacterial defense enzymes). Electrostatic potential maps and docking experiments showed that the 2-nitro group of NV esters could play the role of a carboxylate in the penam series.