Figure 3 - full size

Figure 3.
Figure 3 Interactions in the -catenin -APC-rA complex. (A) Comparison of -catenin-bound APC-rA, XTcf3 and E-cadherin in the core homology region of APC-rA. -catenin residues are labeled in gray boxes. Other colors are as in Figure 2B. Contacts between APC-rA and -catenin are drawn as solid lines (non-polar interactions), dotted lines (hydrogen bonds) or dashed lines (salt bridges). APC-rA residue numbers are indicated in green. (B) Comparison of -catenin bound APC-rA, XTcf3 and E-cadherin in the region of the APC-rA bulge. Coloring and labeling is as in (A). Contacts of -catenin with APC-rA are drawn in gray, and those with XTcf3 and E-cadherin in red. (C) Stabilizing forces in the APC-rA C-terminal bulge. -catenin is drawn in a surface representation, colored blue for positive and red for negative electrostatic potential at the 10 kT/e level. The APC-rA peptide is colored by atom type with carbon white, oxygen red and nitrogen blue. Although no density is seen for the APC-rA Lys1030 or Asp1033 side chains in the structure, they are modeled (gray side chains) to demonstrate their likely interactions with regions of electrostatic potential on the surface of -catenin. Hydrogen bonds between backbone and side chain atoms within the peptide are drawn as dotted lines. The Leu 1029 side chain is not shown for clarity. (A) and (B) were generated using Molscript and Raster3D (Kraulis, 1991; Merrit and Murphy, 1994).