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Predicting the emergence of antibiotic resistance by directed evolution and structural analysis
M C Orencia1, J S Yoon, J E Ness
1Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
Nature Structural Biology
|February 27, 2001
Summary
Directed evolution accurately predicts antibiotic resistance by identifying key mutations. This method, using TEM-1 beta-lactamase, generated a mutation combination equivalent to clinical TEM-52, showing its predictive power.
Area of Science:
- Microbiology
- Biochemistry
- Evolutionary Biology
Background:
- Antibiotic resistance arises from mutations that enhance pathogen fitness while preserving essential protein structures.
- The need to maintain enzyme stability alongside increased activity limits possible mutation pathways.
Purpose of the Study:
- To investigate if directed evolution can predict mutations leading to antibiotic resistance.
- To analyze the structural and functional impact of mutations conferring resistance.
Main Methods:
- Directed evolution of TEM-1 beta-lactamase in a hypermutator E. coli strain using cefotaxime selection.
- Comparison of evolved mutants with previous studies and clinical isolates.
- Structural determination of the resistant TEM-52 enzyme.
Main Results:
- Directed evolution consistently yielded the E104K/M182T/G238S mutation combination, conferring approximately 500-fold resistance.
- This evolved mutation set matched the TEM-52 clinical isolate.
- Structural analysis revealed G238S enhances active site access, E104K stabilizes the enzyme, and M182T acts as a global suppressor.
Conclusions:
- Directed evolution is a powerful tool for predicting antibiotic resistance mutations.
- Coupling directed evolution with structural analysis provides insights into resistance mechanisms and future evolutionary trajectories.