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Novel ceftazidime-resistance beta-lactamases generated by a codon-based mutagenesis method and selection.
Paul Gaytán1, Joel Osuna, Xavier Soberón
1Instituto de Biotecnología/UNAM, Ap. Postal 510-3, Cuernavaca, Morelos 62250, México. paul@ibt.unam.mx
Nucleic Acids Research
|August 15, 2002
Summary
A novel codon-based mutagenesis method efficiently generated 13 beta-lactamases, including new ceftazidime-resistant variants. This approach enables rapid enzyme evolution for antibiotic resistance research.
Area of Science:
- Molecular Biology
- Enzyme Engineering
- Drug Discovery
Background:
- Beta-lactamase enzymes confer resistance to antibiotics like ceftazidime.
- Developing novel beta-lactamases is crucial for understanding and combating antibiotic resistance.
- Existing mutagenesis methods can be inefficient for generating diverse enzyme variants.
Purpose of the Study:
- To develop and validate a novel, automated codon-based mutagenesis approach.
- To generate a library of ceftazidime-resistance beta-lactamases.
- To identify enhanced beta-lactamase variants with significant ceftazidime resistance.
Main Methods:
- A contaminating codon-based mutagenesis strategy was employed during oligonucleotide synthesis.
- Mutant and wild-type codons were combined in a single synthesis column for automation.
- The method was tested using plasmid pUC19 and applied to TEM-1 beta-lactamase mutagenesis.
Main Results:
- Four known and nine new beta-lactamase variants were successfully generated.
- The mutagenesis approach demonstrated random and binomial behavior.
- A triple mutant (R164H:E240K:R241A) showed a 333-fold increase in ceftazidime resistance compared to wild-type.
Conclusions:
- The novel codon-based mutagenesis method is efficient and automatable for generating enzyme variants.
- This approach accelerates the discovery of enzymes with enhanced antibiotic resistance properties.
- The identified beta-lactamase variants contribute to understanding ceftazidime resistance mechanisms.