Figure 3.

Main inhibitory mechanisms of β-lactamase inhibitors (BLIs). 1: The classical BLIs are mainly characterized as suicide inactivators, combining with serine residue at active sites and inactivating β-lactamases. 2: The first generation of non-β-lactam diazabicyclooctane (DBO) BLIs mediate reversible acylation reactions to inhibit SBLs. 3: The second generation of non-β-lactam borate BLIs can form a covalent adduct transition state to reversibly inhibit both serine-β-lactamases (SBLs) and metallo-β-lactamases (MBLs). KPC and OXA denote Klebsiella pneumoniae carbapenemase and oxacillin-hydrolyzing enzymes, respectively.