A SPIN SYSTEM LABELED AND HIGHLY RESOLVED ED-H(CCO)NH-TOCSY EXPERIMENT FOR THE FACILITATED ASSIGNMENT OF PROTON SIDE-CHAINS IN PARTIALLY DEUTERATED SAMPLES
Rm. Gschwind et al., A SPIN SYSTEM LABELED AND HIGHLY RESOLVED ED-H(CCO)NH-TOCSY EXPERIMENT FOR THE FACILITATED ASSIGNMENT OF PROTON SIDE-CHAINS IN PARTIALLY DEUTERATED SAMPLES, Journal of biomolecular NMR, 11(2), 1998, pp. 191-198
The introduction of deuterated and partially deuterated protein sample
s has greatly facilitated the C-13 assignment of larger proteins. Here
we present a new version of the HC(CO)NH-TOCSY experiment, the ed-H(C
CO)NH-TOCSY experiment for partially deuterated samples, introducing a
multi-quantum proton evolution period. This approach removes the main
relaxation source (the dipolar coupling to the directly bound C-13 sp
in) and leads to a significant reduction of the proton and carbon rela
xation rates. Thus, the indirect proton dimension can be acquired with
high resolution, combined with a phase labeling of the proton resonan
ces according to the C-C spin system topology. This editing scheme, in
dependent of the CHn multiplicity, allows to distinguish between proto
n side-chain positions occurring within a narrow chemical shift range.
Therefore this new experiment facilitates the assignment of the proto
n chemical shifts of partially deuterated samples even of high molecul
ar weights, as demonstrated on a 31 kDa protein.