Structure and mode of peptide binding of pheromone receptor PrgZ

Abstract

We present the crystal structure of the pheromone receptor protein PrgZ from Enterococcus faecalis in complex with the heptapeptide cCF10 (LVTLVFV), which is used in signaling between conjugative recipient and donor cells. Comparison of PrgZ with homologous oligopeptide-binding proteins (AppA and OppA) explains the high specificity of PrgZ for hydrophobic heptapeptides versus the promiscuity of peptide binding in the homologous proteins.

FIGURE 1.

A, hydrogen-bonding network forming the binding site for cCF10 (pink) within PrgZ* (teal). B, schematic representation of PrgZ*, with the bound cCF10 ligand in orange and the binding cavity outlined in gray mesh.

FIGURE 2.

DSC scans of PrgZ* without ligand (solid black line), with cCF10 added (dotted blue line), and with iCF10 added (dashed red line). The T_m of each measurement is indicated above each peak.