Minimal Media Reagents

The use of isotope-enriched minimal media to over-express labeled protein in E. coli is the most cost-effective and popular way to produce isotope-enriched protein for NMR studies. Minimal media is easily prepared by the user and consists of M9 salts, vitamins, a nitrogen source (either ammonium chloride or ammonium sulfate), and a carbon source (e.g., typically glucose or glycerol). The carbon source can either be uniform labeled (e.g., 13C6 or D7 glucose) or partially labeled (e.g., 1-13C glucose or 1,3-13C2 glycerol), depending if uniform or partial/sparse labeling for the target protein is desired. The carbon source can be a single compound such as glucose, or a mixture of labeled compounds, such as Celtone powder.