title: Lactococcin MMFII, a novel class IIa bacteriocin produced by Lactococcus lactis MMFII, isolated from a Tunisian dairy product.
abstract: A novel bacteriocin, lactococcin MMFII, produced by Lactococcus lactis MMFII isolated from a Tunisian dairy product had been identified. The bacteriocin was purified to homogeneity from fresh overnight M17 broth culture by sulfate ammonium precipitation, cation-exchange chromatography, sep-pack chromatography and two steps of reverse-phase chromatography. The purified bacteriocin was heat stable, pH resistant and protease sensitive. Its amino acid sequence, obtained by Edman degradation, revealed a 37-amino acid peptide with two cysteine residues in positions 9 and 14 and a calculated mass of 4144.6 Da. Laser desorption mass spectrometry analysis gave a molecular mass of 4142.6, suggesting the presence of a disulfide bond within the purified bacteriocin. Lactococcin MMFII contains the N-terminal YGNGV consensus motif and is active against Listeria. Thus, it belongs to the class IIa bacteriocins figuring the first example of such a bacteriocin produced by a lactococcal strain.
authors.affiliation: Laboratoire de Biochimie et Biologie Moléculaire, Département de Biologie, Faculté des Sciences de Tunis, El Manar, 2092 Tunis, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Ferchichi
authors.forename: J
authors.initials: J
authors.lastname: Frère
authors.forename: K
authors.initials: K
authors.lastname: Mabrouk
authors.forename: M
authors.initials: M
authors.lastname: Manai
mesh_terms: D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D003611:Dairy Products / Q000382:microbiology*; D013294:Lactococcus lactis / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D008087:Listeria / Q000187:drug effects; D008826:Microbial Sensitivity Tests / Q000379:methods / Q000592:standards; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014416:Tunisia
chemical_list: D001430:Bacteriocins