Shown is the recent NMR solution structure of the human XRCC1 NTD repair protein (left, 1xna at the PDB) and a mechanism for interaction with a human DNA polymerase beta-DNA complex (right, 1bpy at the PDB).
The p16 protein is a cyclin dependent protein kinase inhibitor and a tumor suppressor. The p16 structure (1BI7 from the PDB) consists of four ankyrin repeats. Based on a computational analysis (bottom image) of the autonomous folding units in p16, a C-terminal fragment (p16C) in red containing only two ankyrin repeats (top image) has been identified and shown by expression cloning, fragment production, and biophysical characterization, to fold into a native-like structure. The plot shows the Z-score (the higher the better for predicted complete folding) for all possible peptide fragments that have the Y-axis value as the N-terminal residue of the fragment and the X-axis value as the C-terminal residue.