Solid-state NMR studies of molecular recognition at protein-mineral interfaces

The use of nuclear magnetic resonance (NMR) to analyze the structure and crystal recognition mechanisms of an salivary protein model system is described. NMR dipolar coupling measurements are used to obtain high resolution structures for proteins in microcrystalline form, for proteins oriented in lipid bilayers and lipid vesicles and for proteins in fibrillar form. NMR pulse techniques are also capable of reporting the structures of surface-adsorbed proteins and protein-crystal interactions in molecular detail. The investigations of protein mineral interactions are frequently conducted with techniques that characterize the macroscopic behavior of proteins in the presence of mineral crystals. Equilibrium properties are derived via adsorption isotherm measurements, where data are usually analyzed by assuming a simple Langmuir model of protein adsorption onto the crystal faces.