title: Protein export elements from Lactococcus lactis.
abstract: Broad-host-range plasmids carrying alpha-amylase or beta-lactamase reporter genes lacking a signal sequence were used to select export elements from Lactococcus lactis chromosomal DNA that could function as signal sequences. Fragments containing such elements were identified by their ability to direct the export of the reporter proteins in Escherichia coli. Several of the selected export elements were also active in Bacillus subtilis and L. lactis, although the efficiencies depended strongly on the host organism and reporter gene used. The export elements AL9 and BL1 were highly efficient in L. lactis in the expression and secretion of at least two heterologous proteins (Bacillus licheniformis alpha-amylase and E. coli TEM-beta-lactamase). AL9 even permitted growth of this organism on starch as the sole carbon source. Nucleotide sequence analysis of five selected fragments indicated that these encode oligopeptides with the major characteristics of typical signal peptides. The putative expression signals had a limited similarity to previously described expression signals for E. coli, B. subtilis and L. lactis. Differences in both expression and export efficiency are likely to underlie the host-specific effects.
authors.affiliation: Department of Genetics, Centre of Biological Sciences, Haren, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Perez-Martinez
authors.forename: J
authors.initials: J
authors.lastname: Kok
authors.forename: G
authors.initials: G
authors.lastname: Venema
authors.forename: J M
authors.initials: JM
authors.lastname: van Dijl
authors.forename: H
authors.initials: H
authors.lastname: Smith
authors.forename: S
authors.initials: S
authors.lastname: Bron
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000378:metabolism; D013294:Lactococcus lactis / Q000378:metabolism*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012995:Solubility; D013329:Structure-Activity Relationship; D000516:alpha-Amylases / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D021382:Protein Sorting Signals; D000516:alpha-Amylases; D001618:beta-Lactamases