TDRD1 TD3 structure in complex with R45me2 peptide. (A) Cartoon representation of TD3 (blue) in complex with the MILI R45me2 peptide (yellow). Secondary structure elements are labeled in white. The aromatic cage residues (orange) and the sDMA (yellow) are represented as sticks. (B) Superposition of the structures of TD3 (blue), SND1 (magenta), and eTud11 (cyan). The C-terminal helix of SND1 is absent from the other two structures. The different orientations of the distal end of the helix α2 could play a determining role in defining the orientation of the peptide. (C) The N-terminal extension (chocolate color) of TD3 makes a third connection between the Tudor core (left) and SN-like (right) subdomains against which it packs via large hydrophobic residues such as W699, W701, and F704 as shown. (D) Structure-based sequence alignment between TD3 (45r4), eTud11 (PDB code 3NTI), and SND1 (PDB code 3OMC). Residues with similarity above 70% are displayed in red.
