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A multifunctional prokaryotic protein expression system: overproduction, affinity purification, and selective
D J Kroll1, H Abdel-Malek Abdel-Hafiz, T Marcell
1Division of Medical Oncology, University of Colorado Health Sciences Center, Denver 80262.
DNA and Cell Biology
|June 1, 1993
Summary
New pRSET plasmid vectors enable high-level protein expression in prokaryotes. These vectors facilitate purification and detection of recombinant proteins using affinity chromatography and monoclonal antibodies.
Area of Science:
- Molecular Biology
- Protein Expression
- Biochemistry
Background:
- High-level protein expression in prokaryotes is crucial for biochemical studies.
- Existing systems may lack efficient purification and detection methods.
- The T7 RNA polymerase-driven pET system is a foundation for prokaryotic expression.
Purpose of the Study:
- To develop and characterize a series of novel plasmid vectors (pRSET A, B, and C) for enhanced protein expression in prokaryotes.
- To engineer fusion proteins with a multifunctional leader peptide for purification and detection.
- To facilitate molecular cloning and mutagenesis for protein studies.
Main Methods:
- Development of pRSET plasmid vectors (A, B, C) based on the T7 RNA polymerase system.
- Inclusion of a hexahistidyl sequence for Ni(2+)-affinity purification and enterokinase cleavage site.
- Generation of monoclonal antibodies (MAbs) against leader peptide epitopes for immunological detection.
- Utilizing an 11-site polylinker for subcloning and an f1(+) origin for single-stranded DNA synthesis.
- Overexpression and purification of representative fusion proteins in Escherichia coli using Ni2+ affinity chromatography.
Main Results:
- pRSET vectors facilitate high-level expression of recombinant proteins as fusions.
- Purification of fusion proteins was achieved in a single step using Ni2+ affinity chromatography under denaturing and nondenaturing conditions.
- Monoclonal antibodies enabled universal immunological detection of fusion proteins, though selectivity varied between immunoprecipitation and Western blotting.
- The vectors support subcloning and site-directed mutagenesis through a versatile polylinker and origin of replication.
Conclusions:
- The pRSET vectors provide a powerful resource for high-level protein expression in prokaryotes.
- These vectors integrate efficient purification and detection strategies, simplifying protein biochemistry research.
- The system offers flexibility for various protein studies requiring recombinant protein production and analysis.