TY - JOUR
T1 - Structural and mutagenic analysis of metallo-β-lactamase IMP-18
AU - Furuyama, Takamitsu
AU - Nonomura, Haruka
AU - Ishii, Yoshikazu
AU - Hanson, Nancy D.
AU - Shimizu-Ibuka, Akiko
N1 - Publisher Copyright:
Copyright © 2016, American Society for Microbiology. All Rights Reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84983544919&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84983544919&partnerID=8YFLogxK
U2 - 10.1128/AAC.00985-16
DO - 10.1128/AAC.00985-16
M3 - Article
C2 - 27381398
AN - SCOPUS:84983544919
SN - 0066-4804
VL - 60
SP - 5521
EP - 5526
JO - Antimicrobial Agents and Chemotherapy
JF - Antimicrobial Agents and Chemotherapy
IS - 9
ER -