Figure 3 - full size

 

Figure 3.
Figure 3 a, Comparison of the structure of p19^Ink4d closest to the mean with that of 53BP2. The structures are shown in the same orientation as those in Fig. 2 and the C carbons of structurally equivalent residues in ankyrins III and IV from p19^Ink4d and II and III from p53BP2 have been superimposed. The surface-exposed residues of the sequence corresponding to the p16^Ink4a peptide fragment (residues 80-99), previously shown partially to mimic the activity of the intact protein, are shown in yellow (ref. 22, and S. Wick, M. Dubay and L.B., unpublished results). The side chains of residues 91 and 92, which, based on alanine scanning mutagenesis in the peptide^22, most influence the interaction with Cdk4 and Cdk6, are shown in dark blue. b, Protein surfaces of the same p19^Ink4d structure (but now rotated 55 ? about the y-axis compared to that shown in a and Fig. 2) and a model of Cdk4/cyclin D1 (B.O.S., unpublished). Cdk4 is shown in white, cyclin D1 in purple, and Lys 22, Arg 24 and residues 95-97 of Cdk4 are in red; a yellow arrow indicates the position of the active site in Cdk4. These plots were generated using MOLSCRIPT29 and GRASP30.

The above figure is reprinted by permission from Macmillan Publishers Ltd: Nature (1997, 389, 999-0) copyright 1997.