C-13 CHEMICAL-SHIFT TENSOR OF L-TRYPTOPHAN AND ITS APPLICATION TO POLYPEPTIDE STRUCTURE DETERMINATION
F SEPAROVIC, K HAYAMIZU, R SMITH, BA CORNELL
CHEMICAL PHYSICS LETTERS | ELSEVIER SCIENCE BV | Published : 1991
The C-13 chemical shift tensor has been determined for the indole C2 of tryptophan using 14N dipole-coupled C-13 powder spectra. σ33 was found to be perpendicular to the indole ring, and σ22≈6° off the parallel to the NH bond. The principal values for the C-13 chemical shift tensor were found to be δ11 = 202, δ22 = 48 ppm. The results were applied to the analysis of the reduced chemical shift anisotropy obtained from C-13 enriched tryptophans in the polypeptide gramicidin A in phospholipid membranes. © 1991.