FIGURE 5.

Effect of AgrD point mutations on AIP production and AgrB endopeptidase activity. A, AIP production for each mutant (gray bars) expressed in SH1001 (Δagr::Tet). Cell-free supernatants were prepared and tested in the agr inhibition bioassay. For controls, full-length AgrD is shown as a black bar, and the reporter control is shown as a white bar. As an additional control, a construct without AgrD was also included. B, AgrB cleavage of each AgrD C-terminal point mutant. Each AgrD construct was co-expressed in E. coli with AgrB and immunoblotted with anti-His monoclonal antibody. C, helical wheel of AgrD C-terminal 14 residues. Residues are labeled with numbers that coordinate with the position in full-length AgrD. The Glu-34 and Leu-41 residues are shaded gray.