Amino Acids, Precursors and Kits for Methyl Labeling

The use of methyl TROSY techniques, in conjunction with specialized isotopic labeling, have significantly increased the useful molecular weight range available for NMR investigations for the study of large proteins and supramolecular protein complexes. The isotope labeling requirements include protonated methyl groups enriched with ¹³C in an otherwise per-deuterated molecule.  Extensive deuteration is required to reduce T2 relaxation rates to maximize the amount of available magnetization at the start of signal collection.
The introduction of ¹³CH₃ groups in a perdeuterated protein sample may be achieved by several methods.  For in vivo-based protein expression, the addition of deuterated glucose along with the addition of sufficient quantities of methyl-containing amino acid(s) to the D2O-based cell culture medium is critical.  For cell-free protein expression, the labeled amino acid(s) must be present in the amino acid mix used.
CIL is proud to offer a variety of ¹³CH₃, deuterated amino acids for use in methyl TROSY experiments. CIL also offers kits for labeling alanine and ILVA for use in e. coli-based protein expression.  In addition, CIL offers a complete line of alpha keto isobutyric and alpha keto isovaleric acids for ILV labeling. To increase the signal-to-noise greater than two-fold than what can be achieved using the alpha keto isovaleric acids, CIL also offers Pro-S and Pro-R pre-cursors for valine and leucine for use in e. coli cultures.