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Eukaryotic precursor proteins are processed by Escherichia coli outer membrane protein OmpP
1Yale University School of Medicine, Department of Genetics, New Haven, CT, USA. hms@imb-jena.de
European Journal of Biochemistry
|July 20, 1999
Summary
A novel endopeptidase in Escherichia coli K, identified as outer membrane protein OmpP, cleaves eukaryotic precursor proteins. Its specificity is similar to rat mitochondrial processing peptidase (MPP), with an extended three-amino-acid recognition sequence.
Area of Science:
- Microbiology
- Biochemistry
- Proteomics
Background:
- A specific endopeptidase capable of cleaving eukaryotic precursor proteins was identified in Escherichia coli K strains.
- This enzyme was not detected in Escherichia coli B strains.
Purpose of the Study:
- To identify and characterize the novel endopeptidase found in Escherichia coli K.
- To compare its enzymatic properties and cleavage specificity with known processing peptidases.
Main Methods:
- Purification of the endopeptidase.
- Protein sequencing and Western blotting to identify the enzyme.
- Enzymatic assays using mitochondrial precursor proteins to determine cleavage specificity.
Main Results:
- The endopeptidase was identified as the E. coli outer membrane protein OmpP.
- OmpP exhibits similar proteolytic cleavage patterns to rat mitochondrial processing peptidase (MPP).
- The recognition sequence for OmpP cleavage was refined to a three-amino-acid motif (small aliphatic, large hydrophobic, arginine) and appears to require specific substrate structural motifs.
Conclusions:
- E. coli outer membrane protein OmpP possesses endopeptidase activity on eukaryotic precursor proteins.
- OmpP shares functional similarities with mitochondrial processing peptidase (MPP).
- The substrate specificity of OmpP involves a defined amino acid sequence and structural requirements.