Putative binding site for Z-disc proteins. A) Coil representation of Cap32/34 and chicken CapZ illustrating the B-factor distribution of the Cα atoms. B) Surface presentation of chicken CapZ with structural motifs defined and coloured as in Figure 1. Residues that are different between the α-subunit isoforms Capα1 and Capα2 are highlighted in black. These residues cluster in the same part of the α-globule that shows increased B-factors in the chicken CapZ structure.