A. Meissner et Ow. Sorensen, Editing and diagonal peak suppression in three-dimensional HCCH protein NMR correlation experiments, J BIOM NMR, 19(1), 2001, pp. 69-73
A novel three-dimensional (3D) HCCH NMR experiment is introduced. It involv
es C-13-C-13 COSY or TOCSY coherence transfer plus two independent editing
steps according to the number of protons attached to the individual carbons
before and after the C-13-C-13 homonuclear mixing. This double editing lea
ds to simplification of HCCH protein side chain spectra that otherwise are
prone to spectral overlap. Another interesting feature is amino acid select
ivity, i.e. that the presence of certain correlations in a doubly edited HC
CH subspectrum gives a clue as to assignment to a particular subgroup of am
ino acids or segments thereof. Finally, the selection of two different mult
iplicities in the two editing steps leads to diagonal peak suppression in t
he H-1-H-1 (3D spectrum recorded with two H-1 and one C-13 dimension) or th
e C-13-C-13 (3D spectrum recorded with one H-1 and two C-13 dimensions) two
-dimensional projection. The new experiment is demonstrated using a C-13,N-
15-labeled protein sample, chymotrypsin inhibitor 2, at 500 MHz.