The prgQ gene of the Enterococcus faecalis tetracycline resistance plasmid pCF10 encodes a peptide inhibitor, iCF10.
Conjugative transfer of the Enterococcus faecalis tetracycline resistance plasmid pCF10 is stimulated by a peptide pheromone, cCF10. Once a recipient strain acquires pCF10 and thus becomes a pheromone-responsive donor, cCF10 activity is no longer detected in culture filtrates. Here we show that pCF10 encodes a peptide inhibitor, iCF10, secreted by donor cells; this inhibitor antagonizes the cCF10 activity in culture filtrates. In order to detect and quantitate iCF10, we developed a reverse-phase high-performance liquid chromatography assay in which the inhibitor peptide elutes separately from the pheromone; this type of assay enabled us to determine that lack of pheromone activity in donor culture filtrates was due to secretion of a mixture of iCF10 and cCF10, rather than abolition of cCF10 secretion. The gene encoding iCF10, prgQ, is located on the EcoRI-C fragment of pCF10. The open reading frame comprising the prgQ gene encodes a 23-amino-acid precursor that resembles a signal peptide. This precursor is cleaved to the mature heptapeptide iCF10 during the secretion process.
Nakayama
J
J
Department of Agricultural Chemistry, University of Tokyo, Japan.
Ruhfel
R E
RE
Dunny
G M
GM
Isogai
A
A
Suzuki
A
A
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D003227:Conjugation, Genetic / Q000187:drug effects; D013293:Enterococcus faecalis / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D010675:Pheromones / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics* / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics*
D001426:Bacterial Proteins; D009842:Oligopeptides; D010675:Pheromones; D011498:Protein Precursors; D021382:Protein Sorting Signals; C090554:iCF10 peptide precursor, Plasmid pCF10; C057280:peptide pheromone cCF10