文摘
Fibronectin, a large modular protein, interacts with many other proteins in the extracellularmatrix and on the cell surface. It has previously been shown that interactions between noncontiguousmodules exist in the collagen binding region. It is shown here that the interaction between the sixth typeI module (6F1) and the second type II module (2F2) can be disrupted by mutation of a residue in theintermodule interface of the 6F11F22F2 fragment. The perturbation of the interface and the binding ofcollagen-derived peptides to individual modules were assessed by high-resolution nuclear magneticresonance (NMR) spectroscopy. Cooperativity between the modules in binding ligand was assessed byanalytical gelatin affinity chromatography of the mutant and wild-type proteins. Differential scanningcalorimetry (DSC) was used to probe the influence of the interface on module stability. It is shown thatwhile the 6F1-2F2 interface confers significant thermal stability to the 2F2 module, it has little effect ongelatin binding activity of the 6F11F22F2 fragment.