• Journal of the Korean Magnetic Resonance Society
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• v.13 no.1
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• pp.15-26
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• 2009

The NMR detection of methyl groups is of keen interest because they provide the long-range distance information required to establish global folds of high molecular weight proteins. Using longitudinal $^1H$ relaxation optimization, we achieve a gain in sensitivity of approximately 1.6-fold in the methyl-TROSY and its NOESY experiments for the 38 kDa protein mitogen activated protein kinase p38 in its fully protonated and $^{13}C$ and $^{15}N$ labeled state.

• Journal of the Korean Magnetic Resonance Society
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• v.18 no.2
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• pp.47-51
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• 2014

Larger proteins (above molecular weight 50 kDa) usually show slow motional tumbling in solution, which facilitates the decay of NMR signal, resulting in poor signal-to-noise. In the past twenty years, researchers have tried to overcome this problem with higher molecular weight by improvement of hardware (higher magnetic field and cryoprobe), optimization of pulse sequences for lager molecules, and development of isotope-labeling techniques. Actually, GroEL/ES complex (${\approx}$ 900 kDa) was successfully studied using combination of above techniques. Among the techniques used in large molecular studies, the impact of isotope-labeling for large molecules study is summarized and discussed here.