Transforming a drug/H+ antiporter into a polyamine importer by a single mutation
Shlomo Brill1, Ofir Sade Falk, Shimon Schuldiner
1Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
Summary
A single mutation transformed the EmrE multidrug transporter into a polyamine importer. This discovery offers insights into the evolution of transport mechanisms and antibiotic resistance in microbes.
Area of Science:
- Biochemistry
- Microbiology
- Molecular Biology
Background:
- EmrE is a multidrug antiporter in Escherichia coli.
- Antibiotic resistance can emerge through mutations in microbial genes.
- Understanding transporter evolution is key to combating resistance.
Purpose of the Study:
- Investigate the development of novel specificities in multidrug transporters.
- Explore the impact of mutations on EmrE function.
- Characterize the mechanisms of transporter evolution.
Main Methods:
- Directed evolution of EmrE to create a mutant library.
- Screening for resistance to norfloxacin and erythromycin.
- Biochemical analysis of mutant transporter activity.
Main Results:
- A single mutation (Trp to Gly) conferred resistance to erythromycin.
- The mutated EmrE lost drug/H(+) antiporter activity.
- The mutant EmrE functions as an electrochemical potential-driven polyamine importer.
Conclusions:
- Single mutations can drastically alter transporter specificity and function.
- EmrE's transformation provides a model for studying transporter evolution.
- This work sheds light on how microbes develop resistance and adapt.
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