Biomolecular NMR

Selective Labeling

Selective Isotope-Labeling Methods for Protein Structural Studies

  • Selective Isotope-Labeling Methods for Protein Structural Studies
  • Production of U-[2H], Thy-γ2[13CH3] Labeled Proteins for methyl-TROSY NMR (Application Note 39)
  • Isotope Labeling of Alanine Methyl Groups on a Deuterated Background for NMR Studies of High-Molecular-Weight Proteins (Application Note 25)

Selective labeling of a protein is used to simplify crowded spectra in order to aid in spectral interpretation or to provide specific probes for dynamic and structural studies. There are a few procedures available for selective labeling. The most popular method is Amino Acid Type Selective labeling which entails the addition of one or more labeled amino acids (~50->250 mg / L) to unlabeled growth media  prior to protein induction. The cells will generally utilize the supplemented amino acids for protein synthesis prior to undergoing the de novo synthesis of the target amino acids. The only labeled residues in the expressed protein will thus be the amino acid types supplemented to the medium. A different method, Selective Unlabeling, utilizes the addition of one or more unlabeled amino acids to a labeled minimal medium.  Therefore, the expressed protein will be fully labeled except for the residue types corresponding to the unlabeled amino acids that were supplemented to the minimal medium.