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Penicillin binding proteins in Listeria monocytogenes
M F Vicente1, J Berenguer, M A de Pedro
1Department of Microbiology, Ramon y Cajal Hospital, CSIC-UAM, Madrid, Spain.
Acta Microbiologica Hungarica
|January 1, 1990
Summary
Penicillin-binding proteins (PBPs) in Listeria membranes were identified and their antibiotic binding affinities analyzed. Antibiotic concentrations that inhibited PBP labeling correlated with lethal concentrations, explaining Listeria
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Listeria monocytogenes exhibits natural resistance to certain beta-lactam antibiotics.
- Understanding the interaction between antibiotics and bacterial targets is crucial for developing effective treatments.
Purpose of the Study:
- To identify and characterize penicillin-binding proteins (PBPs) in Listeria membranes.
- To investigate the binding patterns of various beta-lactam antibiotics to these PBPs.
- To correlate antibiotic binding affinity with the lethal concentrations and natural resistance of Listeria.
Main Methods:
- Isolation of Listeria membranes from protoplasts.
- Labeling of PBPs using 125I-ampicillin as a radioactive probe.
- Estimation of PBP copy numbers.
- Competitive binding experiments with a panel of beta-lactam antibiotics.
Main Results:
- Eight PBP bands were detected, with molecular weights ranging from 38,000 to 100,000.
- Predominant PBPs were observed at 95,000, 85,000, 60,000, 49,000, and 38,000.
- Ampicillin, piperacillin, and imipenem showed the most effective binding to PBPs.
- Cefotaxime and cefoxitin exhibited very low binding abilities.
Conclusions:
- The binding affinity of beta-lactam antibiotics to Listeria PBPs correlates with their effectiveness in inhibiting bacterial growth.
- This study provides insights into the mechanisms underlying the natural resistance of Listeria to certain beta-lactam compounds.