Figure 1.

Generic DARPin representation.A, schematic representation of a DARPin domain. The designed N- and C-terminal capping repeats and designed self-compatible repeat modules are the building blocks that stack via compatible interfaces. B, the repeat modules stack together forming a continuous hydrophobic core, which is sealed by an N-Cap (green) and a C-Cap (cyan). The repeat domains display variable molecular surfaces (randomized positions, depicted in red), which are potential target-binding sites (1, 2). C, structure of a DARPin (PDB ID: 2XEE (25)) in ribbon representation with the same color scheme as above: helices of the N-terminal capping repeat, the internal repeat modules, and the C-terminal capping repeat are colored green, blue, and cyan, respectively. The side chains of randomized positions are displayed as red sticks. This figure was created with open-source PyMOL (https://github.com/schrodinger/pymol-open-source). DARPin, designed ankyrin repeat protein.