FIGURE 11.

Model for titin Zq domain interaction with the α-actinin R2-R3 central rod domain. This model proposes that loops in the R2 and R3 spectrin repeat-like domains in each of the antiparallel monomers, which lie in proximity on the surface of the central rod with a two-fold symmetry, constitute the binding site for the 26-residue helical region of the Zq domain (yellow). Proximity of two Zq domains interacting with the R2-R3 domain may allow antiparallel interaction of the helical regions of the Zq domains, which may promote stability of the complex.