title: Cloning of usp45, a gene encoding a secreted protein from Lactococcus lactis subsp. lactis MG1363.
abstract: We have cloned usp45, a gene encoding an extracellular secretory protein of Lactococcus lactis subsp. lactis strain MG1363. Unidentified secreted 45-kDa protein (Usp45) is secreted by every mesophilic L. lactis strain we tested so far and it is chromosomally encoded. The nucleotide sequence of the usp45 gene revealed an open reading frame of 1383 bp encoding a protein of 461 amino acids (aa), composed of a 27-aa signal peptide and a mature protein initiated at Asp28. The gene contains a consensus promoter sequence and a weak ribosome-binding site; the latter is rather uncommon for Gram-positive bacteria. Expression studies in Escherichia coli showed efficient synthesis and secretion of the protein. Usp45 has an unusual aa composition and distribution, and it is predicted to be structurally homologous with P54 of Enterococcus faecium. Up to now, no biological activity could be postulated for this secreted protein.
authors.affiliation: Department of Biophysical Chemistry, Netherlands Institute for Dairy Research, NIZO, Ede.
authors.forename: M
authors.initials: M
authors.lastname: van Asseldonk
authors.forename: G
authors.initials: G
authors.lastname: Rutten
authors.forename: M
authors.initials: M
authors.lastname: Oteman
authors.forename: R J
authors.initials: RJ
authors.lastname: Siezen
authors.forename: W M
authors.initials: WM
authors.lastname: de Vos
authors.forename: G
authors.initials: G
authors.lastname: Simons
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000235:genetics*; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; C066583:usp45 protein, Lactococcus lactis