Figure 4.

Primary and secondary receptor binding sites of FGF-2. The binding sites are identified on the basis of site-directed mutagenesis studies (33–35). (a) On the left is the Connolly surface rendering of the FGF-2 molecule with the residues corresponding to the primary site in purple and those corresponding to the secondary site in red. Notice that the secondary site (red) is not visible in this view as it is on the diametrically opposite end of the molecule compared with the primary site. (b) Same molecule as in a but rotated about a vertical axis in the plane of the paper by 180° so as to view the molecule from the other side.