Fig. 4.

Crystal structure of the horseshoe-like motif in the N-terminal domain of mouse Cntn4. A cartoon representing the domain organization of Cntn4 is shown on the left, along with a ribbon diagram in the middle and a surface representation on the right. The letters N and C indicate the N- and C-termini, respectively. Disulfide bonds are shown as orange ball-and-stick models. Asparagine-linked N-acetylglucosamine residues are depicted as gray ball-and-stick models along with the asparagine side chain. Ig domains 1, 2, 3, and 4 are colored cyan, green, gold, and red, respectively. The horseshoe-like structure of Ig domains 1–4 of mouse Cntn4 is closely related to the one adopted by the first four Ig domains of chicken and human Cntn2 and superimpose with rmsd values of 1.6–2.3Å (Freigang et al., 2000; Mortl et al., 2007; Bouyain and Watkins, 2010). Structural images were generated using PyMOL (www.pymol.org).