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Isolation, nucleotide sequence, and expression of a cDNA encoding pig citrate synthase
C T Evans1, D D Owens, B Sumegi
1Pre-Clinical Science Unit, Veterans Administration Medical Center, Dallas, Texas 75216.
Biochemistry
|June 28, 1988
Summary
Researchers cloned and expressed pig citrate synthase cDNA in E. coli, successfully complementing a mutation. This work advances understanding of mitochondrial enzymes and their genetic manipulation for biochemical studies.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Citrate synthase is a crucial Krebs cycle enzyme.
- Its structure and substrate-binding regions are known.
- Mitochondrial signal peptides guide enzyme localization.
Purpose of the Study:
- To clone and sequence the complementary DNA (cDNA) for pig citrate synthase.
- To express the pig citrate synthase gene in Escherichia coli.
- To analyze the N-terminal leader peptide and its role.
Main Methods:
- Screening a pig kidney cDNA library with a synthetic oligonucleotide probe.
- Determining the nucleotide sequence of the cloned cDNA.
- Modifying the cDNA to remove the leader sequence and cloning into an expression vector.
- Transforming an E. coli mutant with the expression plasmid.
Main Results:
- The complete nucleotide sequence of pig citrate synthase cDNA was determined.
- The sequence confirmed the known amino acid sequence and predicted a mitochondrial leader peptide.
- The expressed pig citrate synthase complemented a glutamate-requiring E. coli mutant (gltA).
Conclusions:
- The study successfully cloned, sequenced, and expressed functional pig citrate synthase in E. coli.
- The findings confirm the enzyme's structure and identify a conserved mitochondrial leader peptide sequence.
- This provides a system for studying citrate synthase and its regulation.