Ago2 MC sequence region/eIF4E alignment and structure topologies. (A) The reported  Ago2 MC sequence region alignment (Ago2) to eIF4E (1l8b) is depicted together with an aligned piwi structure sequence (1w9h) and with the BLAST-detected Ce eIF4E-1 sequence (eIF4E). The reported alignment (underlined) differs from the detected BLAST alignment in length and in placement of gaps (Ago2 residues that differ are italicized). BLAST identities and similarities are indicated between the sequences (with | and +, respectively). Differences in gapped regions are marked with slanted lines that pair BLAST residue matches. Sequences are highlighted according to family conservations as in Figure 1, with eIF4E cap stacking residues and the corresponding Ago2 aromatics highlighted magenta. Secondary structural elements derived from the respective structures (arrow for strand and cylinder for helix) are indicated above and below the sequences and colored by rainbow from N-terminus (blue) to C-terminus (red), with the positions of identified aromatic residues marked by a magenta circle. (B and C) Topology diagrams illustrate Ago mid domain (B) and eIF4E (C) connectivity. Secondary structural elements of each fold are colored as in (A). Magenta circles represent the relative positions of aromatic residues. The N-termini and C-termini are labeled.