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A new class of N-rich fused heterocyclic compounds containing the triazolo-triazine moiety was synthesized and studied by cyclic voltammetry, UV/Vis spectroscopy, X-ray diffraction, and first principle computations. All the compounds show reversible or quasi-reversible reduction processes, with reduction potentials easily tunable within the class. LUMO ener-gies as low as –3.95 eV have been measured. The UV/Vis spectra show highly structured absorptions, indicative of rigid molecular skeletons. The solid-state packing is dominated by π–π stacking interactions, which are promoted by weak CAr–H···N interactions, whereas face-to-edge contacts (T contacts), typical of many fused hydrocarbons, are largely absent

PonA2 is one of the two class A penicillin binding proteins of Mycobacterium tuberculosis, the etiologic agent of tuberculosis. It plays a complex role in mycobacterial physiology and is spotted as a promising target for inhibitors. PonA2 is involved in adaptation of M. tuberculosis to dormancy, an ability which has been attributed to the presence in its sequence of a C-terminal PASTA domain. Since PASTA modules are typically considered as β-lactam antibiotic binding domains, we determined the solution structure of the PASTA domain from PonA2 and analyzed its binding properties versus a plethora of potential binders, including the β-lactam antibiotics, two typical muropeptide mimics, and polymeric peptidoglycan. We show that, despite a high structural similarity with other PASTA domains, the PASTA domain of PonA2 displays different binding properties, as it is not able to bind muropeptides, or β-lactams, or polymeric peptidoglycan. These results indicate that the role of PASTA domains cannot be generalized, as their specific binding properties strongly depend on surface residues, which are widely variable.