Figure 5.

The α5 helix may represent a protein-binding site. (a) The known FMRP-interacting motif forms the α5 helix in the homodimeric Caprin-1 structure. The helices are rendered as cylinders. The two protomers are colored red and blue, respectively, except for the two α5 helices, which are highlighted in cyan. The exposed surface of the α5 helix may interact with an FMRP molecule. (b) The α5 helix mediates a protein–protein contact between two adjacent Caprin-1 dimers (orange/magenta and green/cyan) in the crystals.