Figure 3.

Shp2’s backdoor cysteines constitute a buried allosteric site. (A) Partial primary sequence alignment (human Shp2 numbering) of the PTPs that appear in Figure 1A. (B) Three-dimensional structure of the Shp2 catalytic domain (Protein Data Bank entry 3B7O).²⁶ The PTP active site is colored magenta. The enzyme’s solvent-accessible surface is shown but rendered transparently so that the buried C333 and C367 side chains (colored by element) can be visualized.