Cloning and characterization f a region of the Enterococcus faecalis conjugative plasmid, pCF10, encoding a sex pheromone-binding function

In order to investigate the mechanism by which peptide sex pheromones induce expression of the conjugation functions of certain Enterococcusfaecalis plasmids, a biological assay was developed to measure the ability of cells carrying the conjugative plasmid pCF10 to bind the sex pheromone cCF10. The data indicated that pCF10 endows its host E.faecafs cell with the ability to specifically remove (apparently by irreversible binding) cCF10 activity from culture medium. The pCF10 DNA encoding this ability was localized to a 3.4-kb segment within a region involved in negative control of expression of conjugal transfer functions. This segment also encoded ability to bind the pheromone inhibitor peptide iCF1O. DNA sequencing revealed three open reading frames, which have been denotedprgW (pheromone responsive gene W),prgZ, and prgY. The deduced product ofprgW resembled regulatory proteins from other bacteria and eucaryotes, with a very high degree of identity within a putative DNA-binding domain. TheprgY gene actually extended into an adjacent region of pCF10 and could encode a protein with significant similarity to a protein called TraB, believed to be involved in shutdown of pheromone cAD1 production by cells carrying the pheromone-inducible hemolysin plasmid pAD1, according to F. Y. An and D. B. Clewell (Abstr. Gen. Meet. Am. Soc. Microbiol. 1992, H70, 1992). The prgZ gene product showed significant relatedness to binding proteins encoded by oligopeptide permease (opp) operons in gram-positive and gram-negative bacteria and is highly similar to a pADI-encoded protein, TraC, which i