Targeting the Class A Carbapenemase GES-5 via Virtual Screening.

Raphael Klein,Pierangelo Bellio,Laura Cendron,Giuseppe Celenza,Ruth Brenk,Lorenzo Maso,Martina Montanari,Donatella Tondi

doi:10.3390/biom10020304

Abstract

The worldwide spread of β-lactamases able to hydrolyze last resort carbapenems contributes to the antibiotic resistance problem and menaces the successful antimicrobial treatment of clinically relevant pathogens. Class A carbapenemases include members of the KPC and GES families. While drugs against KPC-type carbapenemases have recently been approved, for GES-type enzymes, no inhibitors have yet been introduced in therapy. Thus, GES carbapenemases represent important drug targets. Here, we present an in silico screening against the most prevalent GES carbapenemase, GES-5, using a lead-like compound library of commercially available compounds. The most promising candidates were selected for in vitro validation in biochemical assays against recombinant GES-5 leading to four derivatives active as high micromolar competitive inhibitors. For the best inhibitors, the ability to inhibit KPC-2 was also evaluated. The discovered inhibitors constitute promising starting points for hit to lead optimization.

Highlights

The spread of multidrug resistant (MDR) Gram-negative bacteria is a major public health threat [1]
At the outset of the study, five structures of GES-5 were available in the PDB (PDB codes: 4GNU, 4H8R, 5F82, 5F83, 6Q35) [12,13,14]
It was revealed that ligands cocrystalized with KPC-2 form hydrogen bonds to the amino acids corresponding to Asn127, Ser125 and Thr232 in GES-5

Summary

Introduction

The spread of multidrug resistant (MDR) Gram-negative bacteria is a major public health threat [1]. Β-lactams represent, worldwide, the most used antibiotics against infections caused by Gram-negative bacteria, constituting 40% of all prescribed antibiotics. The continuous emergence of β-lactamases (BLs) such as carbapenemases conferring resistance to almost all available β-lactam antibiotics, poses a serious health threat to the public. Class A carbapenemases include members of the KPC and GES families. KPC- and GES-type enzymes are both plasmid-mediated BLs, disseminating horizontally. While KPC-2 inhibitors are at present available for therapy, no compounds active against GES-type BLs are yet available. GES-type BLs, the target of our study, represent a unique example of this family of hydrolytic enzymes. Because of the documented carbapenemase activity, as well as a structural characteristic shared by other serine carbapenemases

Results

Discussion

Conclusion