title: Molecular basis for control of conjugation by bacterial pheromone and inhibitor peptides.
abstract: In many bacteria expression of lateral gene transfer and of virulence factors is controlled by cell-cell signalling systems. Molecular interactions of microbial signal molecules with their cognate receptors are not well understood. For the Enterococcus faecalis conjugative plasmid pCF10, the PrgX protein serves as a molecular switch controlling expression of conjugation and virulence genes encoded by the plasmid. The induction state of a pCF10-carrying donor cell is determined by the ratio of two signalling peptides, cCF10 pheromone and iCF10 inhibitor. Recent analysis of PrgX/cCF10 interactions suggests a mechanism for conversion to the induced state. However, the means by which iCF10 peptide antagonizes cCF10 activity is unclear, and it has been suggested that inhibitor peptides block import of pheromone peptides. We now show that both of these peptides interact with the same binding pocket of PrgX, but they differentially alter the conformation of the protein and its oligomerization state, resulting in opposing biological activities.
authors.affiliation: Department of Microbiology, 1460 Mayo Memorial Building, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Briana K
authors.initials: BK
authors.lastname: Kozlowicz
authors.forename: Ke
authors.initials: K
authors.lastname: Shi
authors.forename: Zu-Yi
authors.initials: ZY
authors.lastname: Gu
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Ohlendorf
authors.forename: Cathleen A
authors.initials: CA
authors.lastname: Earhart
authors.forename: Gary M
authors.initials: GM
authors.lastname: Dunny
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D003227:Conjugation, Genetic; D004269:DNA, Bacterial; D013293:Enterococcus faecalis / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D007763:Lac Operon; D008958:Models, Molecular; D009154:Mutation; D009842:Oligopeptides / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D010675:Pheromones / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D010957:Plasmids; D011485:Protein Binding; D021382:Protein Sorting Signals / Q000502:physiology*; D018000:Receptors, Peptide / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D009842:Oligopeptides; D010675:Pheromones; D021382:Protein Sorting Signals; D018000:Receptors, Peptide; C090554:iCF10 peptide precursor, Plasmid pCF10; C057280:peptide pheromone cCF10