Production of protein for nuclear magnetic resonance study using the wheat germ cell-free system

Nuclear magnetic resonance (NMR) methods have been developed to determine the three-dimensional structures of proteins, to estimate protein folding, and to discover high-affinity ligands for proteins. However, one of the difficulties encountered in the application of such NMR methods to proteins is that we should obtain milligram quantities of 15N and/or 13C-labeled pure proteins of interest. Here, we describe the method to produce proteins for NMR experiments using the improved wheat germ cell-free system, which exhibits several attractive features for high-throughput NMR study of proteins.