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Updated: Jul 4, 2026
11:39
Identification of Functional Protein Regions Through Chimeric Protein Construction
Published on: January 8, 2019
Linking the functions of unrelated proteins using a novel directed evolution domain insertion method
Wayne R Edwards1, Kathy Busse, Rudolf K Allemann
1School of Biosciences and School of Chemistry, Cardiff University, Cardiff, UK.
Nucleic Acids Research
|June 19, 2008
Summary
Researchers created novel integral protein fusions using a new directed evolution method. This technique generates molecular switches, demonstrated by engineered TEM-1 beta-lactamase exhibiting conditional activity.
Area of Science:
- Protein Engineering
- Synthetic Biology
- Molecular Biology
Background:
- Directed evolution is a powerful tool for protein engineering.
- Integral protein fusions, where one domain is inserted within another, are challenging to create.
- Molecular switches with conditional activity are desirable for various applications.
Purpose of the Study:
- To develop a novel directed evolution method for generating integral protein fusions.
- To construct molecular switches based on inter-dependent protein activities.
- To investigate the impact of insertion sites and linker sequences on fusion protein function.
Main Methods:
- Development of an engineered transposon (MuDel) for random trinucleotide deletion.
- Insertion of a cytochrome b(562) DNA cassette into the bla gene encoding TEM-1 beta-lactamase.
- Characterization of chimeric genes and fusion proteins for retained TEM-1 activity and switching phenotype.
Main Results:
- Successfully generated novel integral protein fusions with retained TEM-1 activity.
- Identified insertion sites within loops and near secondary structure termini (alpha-helices, beta-strands).
- Observed a switching phenotype in Escherichia coli, where ampicillin tolerance depended on haem availability, with a 4- to 128-fold switch magnitude.
Conclusions:
- The developed directed evolution method enables the creation of integral protein fusions.
- These fusions can function as molecular switches with tunable conditional activity.
- Insertion site and linker sequence optimization are crucial for modulating switch performance.
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