An Introduction to Biomolecular Graphics
Figure 4
An intermolecular interface from the M. tuberculosis PE-PPE system (PDB 2G38).
The complex between PE and PPE is shown as a ribbon cartoon (A); the two proteins are colored separately to make the interface evident. Hydrophobic side chains involved in the interface are labeled. The complementary surfaces are illustrated more clearly in (B), by splitting the complex apart like a clamshell (triangular wedge in A). Labels identify the PE and PPE proteins. Hydrophobicity is indicated by grading of cool→warm colors, as shown. Both panels are labeled and depicted on the same scale, so readers can easily see how 3D residue positions at the interface (A) correspond to apolar surface patches in (B).