Structural and Mutagenic Analysis of Metallo-β-Lactamase IMP-18.


IMP-type metallo-β-lactamases (MBLs) are exogenous zinc metalloenzymes that hydrolyze a broad range of β-lactams, including carbapenems. Here we report the crystal structure of IMP-18, an MBL cloned from Pseudomonas aeruginosa, at 2.0-Å resolution. The overall structure of IMP-18 resembles that of IMP-1, with an αβ/βα "folded sandwich" configuration, but the loop that covers the active site has a distinct conformation. The relationship between IMP-18's loop conformation and its kinetic properties was investigated by replacing the amino acid residues that can affect the loop conformation (Lys44, Thr50, and Ile69) in IMP-18 with those occupying the corresponding positions in the well-described enzyme IMP-1. The replacement of Thr50 with Pro considerably modified IMP-18's kinetic properties, specifically those pertaining to meropenem, with the kcat/Km value increased by an order of magnitude. The results indicate that this is a key residue that defines the kinetic properties of IMP-type β-lactamases.

Submission Details


Submitter: Paulie Dang

Submission Date: March 28, 2020, 5:45 p.m.

Version: 1

Publication Details
Furuyama T;Nonomura H;Ishii Y;Hanson ND;Shimizu-Ibuka A,Antimicrob Agents Chemother (2016) Structural and Mutagenic Analysis of Metallo-β-Lactamase IMP-18. PMID:27381398
Additional Information

Explanation of amino acid numbering: Residues K26N, T32P, and I51F that were mutated in this study are called residues K44N, T50P, and I69F respectively in the paper.

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)