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Synthesis of lactococcin 972, a bacteriocin produced by Lactococcus lactis IPLA 972, depends on the expression of a plasmid-encoded bicistronic operon

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Author: Martínez, B. · Fernández, M. · Suárez, J.E. · Rodríguez, A.
Institution: Centraal Instituut voor Voedingsonderzoek TNO
Source:Microbiology, 11, 145, 3155-3161
Identifier: 235201
Keywords: Nutrition · Bacteriocin · Lactococcin 972 · Lactococcus lactis · Plasmid-encoded genes · Lactococcin · Bacterial gene · Gene expression · Lactococcus lactis · Nonhuman · Nucleotide sequence · Operon · Plasmid · Priority journal · Protein synthesis · Structural gene · Amino Acid Sequence · Bacteriocins · Base Sequence · Blotting, Northern · Electrophoresis, Polyacrylamide Gel · Genes, Bacterial · Lactococcus lactis · Molecular Sequence Data · Operon · Plasmids · RNA, Bacterial · Time Factors


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.