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Bacterial Expression and Purification of Calpains
Christian-Scott E McCartney1, Peter L Davies2
1Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
Methods in Molecular Biology (Clifton, N.J.)
|January 9, 2019
Summary
Researchers optimized a protocol for producing recombinant rat calpain-2 in bacteria, yielding 20 mg per 4L culture. This method also facilitates the purification of calpain protease cores, aiding structural studies of related proteins.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Recombinant protein production is crucial for studying protein structure and function.
- Previous efforts to crystallize calpain family members faced challenges.
- Recombinant rat calpain-2 production was key to determining calpain crystal structures.
Purpose of the Study:
- To describe an optimized protocol for producing and purifying recombinant rat calpain-2 from Escherichia coli.
- To present a modified protocol for expressing and purifying calpain protease cores (mini-calpains).
Main Methods:
- Utilized a stable two-plasmid system for heterodimeric enzyme production in E. coli.
- Employed a purification strategy involving anion-exchange, affinity, and size-exclusion chromatography.
- Optimized the protocol order to minimize concentration and dialysis steps.
Main Results:
- Achieved a typical yield of approximately 20 mg of recombinant rat calpain-2 per 4L of E. coli culture.
- Demonstrated the successful production and purification of calpain-1 and calpain-3 protease cores.
- The optimized protocol facilitates structural studies of calpain isoforms and inhibitor interactions.
Conclusions:
- The described protocol provides an efficient method for obtaining substantial quantities of recombinant rat calpain-2.
- The modified protocol enables the study of calpain protease cores, overcoming difficulties in producing full-length proteins.
- These advancements support further structural and functional characterization of the calpain superfamily.
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