Biochemical characterization of IMP-30, a metallo-β-lactamase with enhanced activity toward ceftazidime
Kevin M Pegg1, Eleanor M Liu, Alecander E Lacuran
1Department of Biological Sciences, College of Science, California State Polytechnic University, Pomona, California, USA.
Abstract:
IMP-type enzymes constitute a clinically important family of metallo-β-lactamases that has grown dramatically in the past decade to its current 45 known members. Here, we report the biochemical characterization of IMP-30 in comparison to IMP-1, from which it deviates by a single E59K mutation. Kinetics, MIC assays, docking, and molecular dynamics simulations support a scenario in which Lys59 interacts with the ceftazidime R1 group, resulting in increased water access and enhanced turnover and MIC of ceftazidime.
Insights
The IMP-30 metallo-β-lactamase, differing from IMP-1 by one mutation, shows enhanced activity against ceftazidime. This Lys59 mutation improves drug interaction and enzyme turnover, impacting treatment strategies.
Area of Science:
- Biochemistry
- Molecular Biology
- Drug Discovery
Background:
- Metallo-β-lactamases (MBLs) are clinically significant enzymes conferring antibiotic resistance.
- IMP-type MBLs are a rapidly expanding family with 45 known members.
- Understanding enzyme variants is crucial for combating antimicrobial resistance.
Purpose of the Study:
- To biochemically characterize the IMP-30 metallo-β-lactamase.
- To compare IMP-30 with the well-characterized IMP-1 enzyme.
- To elucidate the structural and functional impact of the E59K mutation on IMP-30 activity.
Main Methods:
- Enzyme kinetics assays
- Minimum Inhibitory Concentration (MIC) assays
- Molecular docking simulations
- Molecular dynamics simulations
Main Results:
- IMP-30, with a single E59K mutation compared to IMP-1, exhibits altered biochemical properties.
- Lysine at position 59 (Lys59) in IMP-30 interacts with the ceftazidime R1 group.
- This interaction enhances water access to the active site, leading to increased enzyme turnover.
- IMP-30 demonstrates enhanced activity and a higher Minimum Inhibitory Concentration (MIC) for ceftazidime.
Conclusions:
- The E59K mutation significantly influences IMP-30's interaction with ceftazidime.
- IMP-30 represents a variant metallo-β-lactamase with potentially altered resistance profiles.
- These findings contribute to understanding MBL evolution and developing strategies against resistant bacteria.
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