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Processing of Kex2 pro-region at two interchangeable cleavage sites
D Germain1, D Y Thomas, G Boileau
1Département de Biochimie, Université de Montréal, Canada.
FEBS Letters
|May 24, 1993
Summary
The Kex2 endoprotease in Saccharomyces cerevisiae requires pro-peptide removal for stability. This processing can occur at either of two cleavage sites, impacting enzyme activity and protein levels.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Protein Processing
Background:
- Kex2 endoprotease (Kex2p) in Saccharomyces cerevisiae is crucial for alpha-pheromone maturation.
- Kex2p also processes its own pro-region, a key step for enzyme function.
- Kex2p exhibits specificity for basic amino acid residues at cleavage sites.
Purpose of the Study:
- To investigate the role of Kex2p pro-region processing sites in enzyme activity and stability.
- To determine if specific cleavage sites are essential for Kex2p maturation.
- To understand the impact of mutations at putative processing sites on Kex2p function.
Main Methods:
- Expression of Kex2p processing site mutants in Saccharomyces cerevisiae.
- Assay of active Kex2p production.
- Analysis of enzyme activity and protein levels in mutant strains.
Main Results:
- Mutations at individual putative cleavage sites did not affect Kex2p activity.
- Mutations at both putative cleavage sites significantly reduced Kex2p activity and protein levels.
- Pro-peptide removal is essential for the production of stable Kex2p.
Conclusions:
- The removal of the Kex2p pro-peptide is necessary for generating a stable enzyme.
- Either of the two identified processing sites can facilitate pro-peptide removal.
- Dual mutations affecting both sites impair Kex2p stability and function.