title: Genetic analysis of a lactococcal plasmid replicon.
abstract: The sequence and genetic organization was determined of the 2508 bp lactococcal portion of pFX2, which was derived from a cryptic Lactococcus lactis subsp. lactis plasmid and used as the basis for construction of a series of lactococcal vectors. A lactococcal plasmid plus origin and two replication protein-coding regions (repA and repB) were located. RepA has a helix-turn-helix motif, a geometry typical of DNA-binding proteins. RepB shows a high degree of homology to the plasmid replication initiation proteins from other gram-positive bacteria and Mycoplasma. The transcribed inverted repeat sequence between repA and repB could form an attenuator to regulate pFX2 replication. Up-stream of the ori site, and in a region which was non-essential for replication, a 215 bp sequence identical to the staphylococcal plasmid pE194 and carrying the RSA site was identified. The genetic organization of this lactococcal plasmid replicon shares significant similarity with pE194 group plasmids.
authors.affiliation: Department of Biotechnology, Massey University, Palmerston North, New Zealand.
authors.forename: F F
authors.initials: FF
authors.lastname: Xu
authors.forename: L E
authors.initials: LE
authors.lastname: Pearce
authors.forename: P L
authors.initials: PL
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004265:DNA Helicases; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D011487:Protein Conformation; D011506:Proteins; D012093:Replicon; D012097:Repressor Proteins / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011506:Proteins; C048817:RepB protein, Bacteria; D012097:Repressor Proteins; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases