Nucleotide sequence and characterization of the cell envelope proteinase plasmid in Lactococcus lactis subsp. cremoris HP.
OBJECTIVE
The major cell envelope proteinase (lactocepin; EC 3.4.21.96) produced by Lactococcus lactis cheese starter bacteria is required for starter growth and acid production in milk. The aim of this study was to characterize a lactocepin plasmid from a L. lactis subsp. cremoris cheese starter strain.


RESULTS
A restriction map of the lactocepin plasmid pHP003 from strain HP was constructed, fragments were cloned in Escherichia coli vectors, and the complete DNA sequence (13,433 bp) was determined. Among 120 industrial L. lactis starter strains screened, five contained the same specificity-type lactocepin as pHP003. The lactocepin gene in these strains was invariably linked with a partially-deleted abiB gene.


CONCLUSIONS
The lactocepin specificity type of strain HP, conferred by a known configuration of key residues, is relatively uncommon. The gene is invariably linked with a partially deleted abiB gene on each lactocepin plasmid.


CONCLUSIONS
This is the first complete sequence reported for a lactocepin plasmid, and provides the basis for better understanding, or manipulation, of lactocepin production.
Christensson
C
C
Institute of Molecular BioSciences, Palmerstown North, Massey University, New Zealand.
Pillidge
C J
CJ
Ward
L J
LJ
O'Toole
P W
PW
D000818:Animals; D001435:Bacteriophages / Q000235:genetics; D002462:Cell Membrane / Q000201:enzymology*; D002611:Cheese / Q000382:microbiology*; D004261:DNA Replication; D005798:Genes, Bacterial / Q000235:genetics; D005814:Genes, Viral / Q000235:genetics; D013294:Lactococcus lactis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics* / Q000821:virology; D008892:Milk / Q000382:microbiology; D010641:Phenotype; D010957:Plasmids / Q000235:genetics*; D012697:Serine Endopeptidases / Q000235:genetics*
D012697:Serine Endopeptidases; C085783:lactocepin