Interface characterization of the type II module pair from fibronectin

The lone ¹F2 ²F2 modular pair of fibronectin is found in the collagen- binding region. This exclusive localization suggests the ¹F2 ²F2 pair plays an important role in the recognition of collagen. However, no information is currently available about the interaction between the two F2 modules and, thus, the orientation of their putative collagen-binding sites with respect to one another. Comparison of a variety of high-resolution NMR parameters from the F2 modules in isolation and the ¹F2 ²F2 pair was used to establish the extent of interaction between the F2 modules in the pair. Chemical shifts of the F2 modules and the ¹F2 ²F2 pair indicate that the structures of the modules are preserved in the pair and that, with the exception of the covalent linkage, they do not interact. ¹⁵N NMR relaxation data identify significant motion occurring in the linker region of the ¹F2 ²F2 pair, and analyses of the anisotropic diffusion properties of the ¹F2 ²F2 pair are consistent with the modules in the F2 pair tumbling independent of one another.