Studies On The Screening Of ?-lactamase Inhibitors And Chemical Labeling Based On Carbapenem Probes

The intensive application of ?-lactam antibiotics has led a significant selection pressure,resulting in the emergence and rapid spread of ?-lactam-resistant bacterial pathogens,which poses a serious threat to human life and health.The primary mechanism for bacterial resistance to P-lactam antibiotics involves the acquisition and expression of ?-lactamases?-lactamases can be divided into serine-?-lactamase(SBLs)and metallo-?-lactamases(MBLs).Most MBLs can hydrolyze almost all the ?-lactam antibiotics.What's more,there is currently no available inhibitor for MBLs in clinical practice.In this work,using a carbapenem-based fluorogenic probe CPC-1 as substrate,we developed a highly sensitive inhibitor screening assay that can be applied to all types of MBLs,especially for B2 MBLs The efciency of this assay was demonstrated by the rapid inhibition screening of a number of molecules against B2 MBL CphA,from which we identifed 2,3-dimercaprol as the most potent molecule with the IC50 of 7.8±0.3 ?M.This assay exhibits great promise to accelerate the screening process for clinically important MBL inhibitors,particularly B2 MBLsFurthermore,?-lactamase chemical labeling system is widely used in protein labeling,and serine ?-lactamase TEM-1 can form covalent bonds with carbapenems.Through a series of experiments,we proved that carbapenem-based compound CB-1 can be used as a selective ligand of the TEM-1 ?-lactamase chemical labeling to achieve selective fluorescence localization in living cells.