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Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G
(1) Background: Metallo-β-lactamases (MBLs) have raised concerns due to their ability to inactivate carbapenems and newer generation cephalosporins and the absence of clinically available MBL inhibitors. Their genes are often transferred horizontally, and the number of MBL variants has grown exponen...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6920813/ https://www.ncbi.nlm.nih.gov/pubmed/31718049 http://dx.doi.org/10.3390/biom9110724 |
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author | Zhang, Charles J. Faheem, Mohammad Dang, Paulie Morris, Monica N. Kumar, Pooja Oelschlaeger, Peter |
author_facet | Zhang, Charles J. Faheem, Mohammad Dang, Paulie Morris, Monica N. Kumar, Pooja Oelschlaeger, Peter |
author_sort | Zhang, Charles J. |
collection | PubMed |
description | (1) Background: Metallo-β-lactamases (MBLs) have raised concerns due to their ability to inactivate carbapenems and newer generation cephalosporins and the absence of clinically available MBL inhibitors. Their genes are often transferred horizontally, and the number of MBL variants has grown exponentially, with many newer variants showing enhanced enzyme activity or stability. In this study, we investigated a closely related group of variants from the IMP family that all contain the combination of mutations S115T and S119G relative to IMP-1. (2) Methods: The effects of each individual mutation and their combination in the IMP-1 sequence background in comparison to IMP-1 were investigated. Their ability to confer resistance and their in-cell expression levels were determined. All enzymes were purified, and their secondary structure and thermal stability were determined with circular dichroism. Their Zn(II) content and kinetic constants with a panel of β-lactam antibiotics were determined. (3) Results: All four enzymes were viable and conferred resistance to all antibiotics tested except aztreonam. However, the single-mutant enzymes were slightly deficient, IMP-1S115T due to decreased enzyme activity and IMP-1-S119G due to decreased thermal stability and expression, while the double mutant did not show these defects. (4) Conclusions: These observations suggest that S119G was acquired due to its increased enzyme activity and S115T to suppress the thermal stability and expression defect introduced by S119G. |
format | Online Article Text |
id | pubmed-6920813 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-69208132019-12-24 Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G Zhang, Charles J. Faheem, Mohammad Dang, Paulie Morris, Monica N. Kumar, Pooja Oelschlaeger, Peter Biomolecules Article (1) Background: Metallo-β-lactamases (MBLs) have raised concerns due to their ability to inactivate carbapenems and newer generation cephalosporins and the absence of clinically available MBL inhibitors. Their genes are often transferred horizontally, and the number of MBL variants has grown exponentially, with many newer variants showing enhanced enzyme activity or stability. In this study, we investigated a closely related group of variants from the IMP family that all contain the combination of mutations S115T and S119G relative to IMP-1. (2) Methods: The effects of each individual mutation and their combination in the IMP-1 sequence background in comparison to IMP-1 were investigated. Their ability to confer resistance and their in-cell expression levels were determined. All enzymes were purified, and their secondary structure and thermal stability were determined with circular dichroism. Their Zn(II) content and kinetic constants with a panel of β-lactam antibiotics were determined. (3) Results: All four enzymes were viable and conferred resistance to all antibiotics tested except aztreonam. However, the single-mutant enzymes were slightly deficient, IMP-1S115T due to decreased enzyme activity and IMP-1-S119G due to decreased thermal stability and expression, while the double mutant did not show these defects. (4) Conclusions: These observations suggest that S119G was acquired due to its increased enzyme activity and S115T to suppress the thermal stability and expression defect introduced by S119G. MDPI 2019-11-11 /pmc/articles/PMC6920813/ /pubmed/31718049 http://dx.doi.org/10.3390/biom9110724 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Zhang, Charles J. Faheem, Mohammad Dang, Paulie Morris, Monica N. Kumar, Pooja Oelschlaeger, Peter Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G |
title | Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G |
title_full | Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G |
title_fullStr | Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G |
title_full_unstemmed | Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G |
title_short | Mutation S115T in IMP-Type Metallo-β-Lactamases Compensates for Decreased Expression Levels Caused by Mutation S119G |
title_sort | mutation s115t in imp-type metallo-β-lactamases compensates for decreased expression levels caused by mutation s119g |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6920813/ https://www.ncbi.nlm.nih.gov/pubmed/31718049 http://dx.doi.org/10.3390/biom9110724 |
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