Overview of the chromodomains of human polycomb paralogs
CBX2,
CBX4, CBX6, CBX7, and CBX8. (A) Structural alignments show the overall
similarity of CBX proteins (magenta = CBX2, pdb code 3H91; gray = CBX4, pdb
code 3I8Z; yellow
= CBX6, pdb code 3I90; purple = CBX7, pdb code 4MN3; salmon = CBX8, pdb code 3I91). (B) Overlay of the aromatic cages with
the Kme3 native ligand in green. (CBX4 not shown, as the only available
structure lacks bound Kme3 ligand.) (C) Overlay of the (−2)
pocket floor Val/Ala residues. (D) Depiction of (−2) pocket
size in each CBX protein with histone 3 alanine 25 as the native ligand.
CBX7 numbering used throughout.