Figure 4

Interaction of Rv0679c peptides with target cells. (A) Binding profiles of peptides derived from Rv0679c to A549 and U937 cells. The slope of the specific binding curve is represented by the length of the black horizontal bars shown in front of each peptide sequence. Peptides showing a slope ≥1% were considered to be HABPs. Numbers shown in the first column correspond to our institute's serial numbering system. Superscripts at the beginning and end of the sequence indicate the peptide amino acid position within the protein. (B) Saturation binding curves for HABPs 30979 and 30987 binding with high activity to U937 cells. Saturation curves were obtained by plotting the specifically bound ¹²⁵I-HABP concentration versus free ¹²⁵I-HABP. Affinity constants and the maximum number of binding sites per cell were obtained from these curves. Inset: the abscissa is log F in the Hill plot and the ordinate is log [B/(B_m - B)], where B_m is the maximum amount of bound peptide, B is the amount of bound peptide and F is the amount of free peptide.