| Title: | Molecular mechanism of peptide-specific pheromone signaling in Enterococcus faecalis: functions of pheromone receptor TraA and pheromone-binding protein TraC encoded by plasmid pPD1 |
| Author(s): | Nakayama J; Takanami Y; Horii T; Sakuda S; Suzuki A; |
| Address: | "Department of Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, University of Tokyo, Japan. ajiro@hongo.ecc.u-tokyo.ac.jp" |
| DOI: | 10.1128/JB.180.3.449-456.1998 |
| ISSN/ISBN: | 0021-9193 (Print) 1098-5530 (Electronic) 0021-9193 (Linking) |
| Abstract: | "Conjugative transfer of the Enterococcus faecalis plasmid pPD1 is activated by cPD1, one of several peptide sex pheromones secreted by plasmid-free recipient cells, and is blocked by a donor-produced peptide inhibitor, iPD1. Using a tritiated pheromone, [3H]cPD1, we investigated how pPD1-harboring donor cells receive these peptide signals. Donor cells rapidly incorporated [3H]cPD1. The cell extract but not the membrane fraction of the donor strain exhibited significant [3H]cPD1-binding activity. On the basis of these data and those of tracer studies, it was demonstrated that cPD1 was internalized, where it bound to a high-molecular-weight compound. The cell extract of a strain carrying the traA-bearing multicopy plasmid (pDLHH21) also exhibited high [3H]cPD1-binding activity. A recombinant TraA exhibited a dissociation constant of 0.49 +/- 0.08 nM against [3H]cPD1. iPD1 competitively inhibited [3H]cPD1 binding to TraA, whereas pheromones and inhibitors relating to other plasmid systems did not. These results show that TraA is a specific intracellular receptor for cPD1 and that iPD1 acts as an antagonist for TraA. A strain carrying the traC-bearing multicopy plasmid (pDLES23) exhibited significant [3H]cPD1-binding activity. A strain carrying traC-disrupted pPD1 (pAM351CM) exhibited lower [3H] cPD1-binding activity as well as lower sensitivity to cPD1 than a wild-type donor strain. Some of the other pheromones and inhibitors inhibited [3H]cPD1 binding to the traC transformant like cPD1 and iPD1 did. These results show that TraC, as an extracellular less-specific pheromone-binding protein, supports donor cells to receive cPD1" |
| Keywords: | "Bacterial Outer Membrane Proteins/genetics/*metabolism Bacterial Proteins/*metabolism Binding, Competitive Cell Extracts Cell Membrane/metabolism Enterococcus faecalis/genetics/*metabolism Fimbriae Proteins Frameshift Mutation Oligopeptides/biosynthesis/*;" |
| Notes: | "MedlineNakayama, J Takanami, Y Horii, T Sakuda, S Suzuki, A eng Research Support, Non-U.S. Gov't 1998/02/11 J Bacteriol. 1998 Feb; 180(3):449-56. doi: 10.1128/JB.180.3.449-456.1998" |
