Author for correspondence: Ana Rodrı́guez. Tel: +34 98 589 21 31. Fax: +34 98 589 22 33. e-mail: iplacsic@greencom.net
aPresent ddress: TNO Nutrition nd Food Reserch Institute, Deprtment of Moleculr Genetics nd Gene Technology, PO Box 360, Utrechtseweg 48, 3700 AJ Zeist, The Netherlnds.
Synthesis of lactococcin 972 is plasmid-encoded. An operon composed of two genes that encode pre-bacteriocin and a putative immunity protein has been identified. The first gene encodes a 91-residue polypeptide that is exported via a sec-dependent system to give the mature 66-aa bacteriocin. The immunity protein is a 563-residue polypeptide with seven potential transmembrane domains. Two transcripts were observed from this region: one comprises the whole operon and is synthesized during the exponential phase of growth while the other, which corresponds just to the bacteriocin structural gene, presents a maximum in exponential cultures but is still present in late-stationary-phase cells.
van BelkumM. J., KokJ., VenemaG.1992; Cloning, sequencing and expression in Escherichia coli of lcnB, a third bacteriocin determinant from the lactococcal bacteriocin plasmid p9B4-6. Appl Environ Microbiol 58:572–577
ChangA. C., CohenS. N.1978; Construction and characterization of amplifiable multicopy DNA cloning vehicles derived from the P15 cryptic miniplasmid. J Bacteriol 134:1141–1156
CintasL. M., CasausP., HavarsteinL. S., Hernández,P. E., NesI. F.1997; Biochemical and genetic characterization of enterocin P, a novel sec-dependent bacteriocin from Enterococcus faecium P13 with a broad antimicrobial spectrum. Appl Environ Microbiol 63:4321–4330
DowerW. J., MillerJ. F., RagsdaleC. W.1988; High efficiency transformation of E. coli by high voltage electroporation. Nucleic Acids Res 16:6127–6145[CrossRef]
DufourA., ThuaultD., BoulliouA., BourgeoisC. M., Le PennecJ. P.1991; Plasmid-encoded determinants for bacteriocin production and immunity in a Lactococcus lactis strain and purification of the inhibitory peptide. J Gen Microbiol 137:2423–2429[CrossRef]
GassonM. J.1983; Plasmid complements of Streptococcus lactis NCDO 712 and other lactic streptococci after protoplast-induced curing. J Bacteriol 154:1–9
HavarsteinL. S., HoloH., NesI. F.1994; The leader peptide of colicin V shares consensus sequences with leader peptides that are common among peptide bacteriocins produced by Gram-positive bacteria. Microbiology 140:2383–2389[CrossRef]
KuipersO. P., RollemaH. S., BeerthuyezenM. M., SiezenR. J., de VosW. M.1995; Protein engineering and biosynthesis of nisin and regulation of the transcription of the structural nisA gene. . Int Dairy J 5:785–795[CrossRef]
LeerR. J., van der VossenJ. M. B. M., van GiezenM., van NoortJ. M., PouwelsP.1995; Genetic analysis of acidocin B, a novel bacteriocin produced by Lactobacillus acidophilus. . Microbiology 141:1629–1635[CrossRef]
Martı́nez, B., Suárez,J. E., Rodrı́guez,A.1996; Lactococcin 972, a homodimeric lactococcal bacteriocin whose primary target is not the plasma membrane. Microbiology 142:2393–2398[CrossRef]
O’SullivanD. J., KlaenhammerT. R.1993; Rapid mini-prep isolation of high-quality plasmid DNA from Lactococcus and Lactobacillus spp. Appl Environ Microbiol 59:2730–2733
RaS. R., QiaoM., ImmonenT., PujanaI., SarisP. E. J.1996; Genes responsible for nisin synthesis, regulation and immunity form a regulon of two operons and are induced by nisin in Lactococcus lactis N8. Microbiology 142:1281–1288[CrossRef]
RauchP. J. G., de VosW. M.1992; Characterization of the novel nisin-sucrose conjugative transposon Tn5276 and its insertion in Lactococcus lactis. . J Bacteriol 174:1280–1287
SchäggerH., von JagowG.1987; Tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the separation of proteins in the range from 1 to 100 kDa. Anal Biochem 166:368–379[CrossRef]
WoroboR. W., van BelkumM. J., SailerM., RoyK. L., VederasJ. C., StilesM. E.1995; A signal peptide secretion-dependent bacteriocin from Carnobacterium divergens. . J Bacteriol 177:3143–3149
Synthesis of lactococcin 972, a bacteriocin produced by Lactococcus lactis IPLA 972, depends on the expression of a plasmid-encoded bicistronic operonThe GenBank accession number for the sequence reported in this paper is AJ002203.