Molecular characterization of a novel bacteriocin and an unusually large aggregation factor of Lactobacillus paracasei subsp. paracasei BGSJ2-8, a natural isolate from homemade cheese.
Screening the collection of natural isolates from semi-hard homemade cheese resulted in isolation and characterization of strain Lactobacillus paracasei subsp. paracasei BGSJ2-8. The strain BGSJ2-8 harbors several important phenotypes, such as bacteriocin production, aggregation phenomenon, and production of proteinase. Bacteriocin SJ was purified by three-step chromatography. Mass spectrometry established molecular mass of the active peptide at 5372 Da. The auto-aggregation phenotype of wild-type (WT) strain was mediated by secreted aggregation-promoting factor (protein of molecular mass > 200 kDa), probably acting in cooperation with other cell surface protein(s). Comparative study of WT and its spontaneous nonaggregating derivative revealed that aggregation factor was responsible for the observed differences in the bacteriocin and proteinase activities. Bacteriocin SJ activity and resistance to different stresses were higher in the presence of aggregating factor. In contrast, proteinase activity was stronger in the nonaggregating derivative.
Institute of Molecular Genetics and Genetic Engineering, Vojvode Stepe 444a, PO Box 23, 11010, Belgrade, Serbia.
Jelena
J
Lozo
Branko
B
Jovcic
Milan
M
Kojic
Michèle
M
Dalgalarrondo
Jean-Marc
JM
Chobert
Thomas
T
Haertlé
Ljubisa
L
Topisirovic
D001426:Bacterial Proteins / Q000737:chemistry*; D001430:Bacteriocins / Q000235:genetics*; D002611:Cheese / Q000382:microbiology*; D010450:Endopeptidases / Q000737:chemistry; D007778:Lactobacillus / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
D001426:Bacterial Proteins; D001430:Bacteriocins; D010450:Endopeptidases