Sensitivity to the two-peptide bacteriocin lactococcin G is dependent on UppP, an enzyme involved in cell-wall synthesis.
Most bacterially produced antimicrobial peptides (bacteriocins) are thought to kill target cells by a receptor-mediated mechanism. However, for most bacteriocins the receptor is unknown. For instance, no target receptor has been identified for the two-peptide bacteriocins (class IIb), whose activity requires the combined action of two individual peptides. To identify the receptor for the class IIb bacteriocin lactococcin G, which targets strains of Lactococcus lactis, we generated 12 lactococcin G-resistant mutants and performed whole-genome sequencing to identify mutations causing the resistant phenotype. Remarkably, all had a mutation in or near the gene uppP (bacA), encoding an undecaprenyl pyrophosphate phosphatase; a membrane protein involved in peptidoglycan synthesis. Nine mutants had stop codons or frameshifts in the uppP gene, two had point mutations in putative regulatory regions and one caused an amino acid substitution in UppP. To verify the receptor function of UppP, it was shown that growth of non-sensitive Streptococcus pneumoniae could be inhibited by lactococcin G when L. lactis uppP was expressed in this bacterium. Furthermore, we show that the related class IIb bacteriocin enterocin 1071 also uses UppP as receptor. The approach used here should be broadly applicable to identify receptors for other bacteriocins as well.
Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, 1432, Ås, Norway; Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
Morten
M
Kjos
Camilla
C
Oppegård
Dzung B
DB
Diep
Ingolf F
IF
Nes
Jan-Willem
JW
Veening
Jon
J
Nissen-Meyer
Tom
T
Kristensen
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001430:Bacteriocins / Q000494:pharmacology*; D002473:Cell Wall / Q000378:metabolism*; D004252:DNA Mutational Analysis; D024881:Drug Resistance, Bacterial; D016680:Genome, Bacterial; D013294:Lactococcus lactis / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D010457:Peptidoglycan / Q000378:metabolism*; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D008565:Membrane Proteins; D010457:Peptidoglycan; C110915:lactococcin G; D011755:Pyrophosphatases; C503879:undecaprenyl pyrophosphate phosphatase