Production of proteins for NMR studies using the wheat germ cell-free system

This chapter describes protocols for preparing 15N-labeled proteins (ubiquitin is used as an example) using Escherichia coli cells (with purification) and the wheat germ cell-free system (without purification). A comparison of 1H-15N heteronuclear single-quantum coherence (HSQC) spectra of yeast ubiquitin prepared using each method indicates that this wheat germ cell-free system may be used for rapid nuclear magnetic resonance analyses of proteins without purification.