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Engineering signal peptides for enhanced protein secretion from Lactococcus lactis
Daphne T W Ng1, Casim A Sarkar
1Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Applied and Environmental Microbiology
|November 6, 2012
Summary
Researchers engineered the Lactococcus lactis Usp45 signal peptide to enhance protein secretion. This improved secretion by up to 51%, offering new strategies for biotechnological applications.
Area of Science:
- Biotechnology
- Molecular Biology
- Microbial Engineering
Background:
- Lactococcus lactis is a key host for protein production and therapeutic delivery.
- Maximizing extracellular protein secretion is crucial for these applications.
- The Usp45 signal peptide is commonly used but has limitations.
Purpose of the Study:
- To identify limitations of the Usp45 signal peptide (Usp45sp) for protein secretion.
- To engineer Usp45sp for increased recombinant protein secretion in L. lactis.
- To develop strategies for enhancing protein secretion in bacterial hosts.
Main Methods:
- Extensive mutagenesis of Usp45sp, including silent and amino acid substitutions.
- Screening signal peptides using Staphylococcus aureus nuclease secretion levels.
- Evaluating top candidates for Bacillus subtilis α-amylase secretion.
Main Results:
- Silent mutations alone increased α-amylase secretion by up to 16% via enhanced translation.
- Engineered Usp45sp variants achieved up to 51% higher maximum secretion.
- The best variant maintained high secretion at lower induction levels and had an increased n-region positive charge.
Conclusions:
- This study presents the first engineered L. lactis signal peptide surpassing Usp45sp secretion yield.
- Strategies for enhancing protein secretion in bacterial hosts were identified.
- Optimized signal peptides offer improved biotechnological production and therapeutic delivery.
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