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Protein export elements from Lactococcus lactis
G Perez-Martinez1, J Kok, G Venema
1Department of Genetics, Centre of Biological Sciences, Haren, The Netherlands.
Molecular & General Genetics : MGG
|September 1, 1992
Summary
Researchers identified novel bacterial export elements from Lactococcus lactis DNA. These elements efficiently secrete heterologous proteins in L. lactis, with one enabling starch utilization.
Area of Science:
- Microbiology
- Molecular Biology
- Biotechnology
Background:
- Identifying and characterizing protein export signals is crucial for microbial biotechnology.
- Lactococcus lactis is a key organism in food fermentation, but its protein secretion systems are not fully understood.
Purpose of the Study:
- To identify and characterize novel functional export signal sequences from Lactococcus lactis chromosomal DNA.
- To evaluate the efficiency and host-specificity of these identified export elements in different bacterial hosts.
Main Methods:
- Utilized broad-host-range plasmids with reporter genes (alpha-amylase, beta-lactamase) to screen L. lactis chromosomal DNA fragments.
- Assessed reporter protein export in Escherichia coli, Bacillus subtilis, and L. lactis.
- Performed nucleotide sequence analysis of identified export elements.
Main Results:
- Several DNA fragments encoding functional export elements were identified and confirmed in E. coli.
- Selected export elements, particularly AL9 and BL1, demonstrated high efficiency in L. lactis for secreting heterologous proteins (B. licheniformis alpha-amylase, E. coli TEM-beta-lactamase).
- Export element AL9 enabled L. lactis to utilize starch as a sole carbon source, indicating robust secretion capabilities.
Conclusions:
- Novel, efficient signal sequences for protein export in L. lactis have been identified from its chromosomal DNA.
- The efficiency of these export elements is host-dependent and influenced by the reporter gene.
- These findings have significant implications for enhancing heterologous protein production in L. lactis and related bacteria.
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