FIGURE 7.

The ⁶⁵PHRP⁶⁸ motif within the N-terminal region of the BMP-7 PD is required for competition with the BMP type II receptor for GF binding. A, scheme of the experimental set-up. Full-length BMP-7 PD (residues 30–292) and the N-terminal truncation variant 65–292 were immobilized, and 100 nm BMP-7 GF was injected in the presence of 0–500 nm BMPRII receptor extracellular domain onto the chip first, followed by a second injection of 100 nm mAb anti-BMP-7 GF antibody to detect bound GF (all injections were in HBS-EP buffer). B, sensorgrams of 100 nm injected mAb anti-BMP-7 GF antibody to detect bound GF. C, increasing amounts of receptor resulted in comparable inhibition of GF binding to both immobilized PD variants, suggesting that the presence of the ⁶⁵PHRP⁶⁸ motif in 65–292 is responsible for PD competition with the type II receptor for the same binding site on the GF. Error bars, S.D. from three independent experiments. The schematic shows GF (orange) and type II receptor (blue) binding sites.