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Extending the range of amide proton relaxation dispersion experiments in proteins using a constant-time relaxation-compensated CPMG approach
被引:135
|作者:
Ishima, R
[1
]
Torchia, DA
[1
]
机构:
[1] Natl Inst Dent & Craniofacial Res, Struct Mol Biol Unit, NIH, Bethesda, MD 20892 USA
关键词:
chemical exchange;
conformational change;
NMR;
CPMG;
R-2;
D O I:
10.1023/A:1022851228405
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
Relaxation compensated constant-time Carr-Purcell-Meiboom-Gill relaxation dispersion experiments for amide protons are presented that detect mus-ms time-scale dynamics of protein backbone amide sites. Because of their ten-fold larger magnetogyric ratio, much shorter 180degrees pulses can be applied to H-1 than to N-15 spins; therefore, off-resonance effects are reduced and a wider range of effective rf fields can often be used in the case of H-1 experiments. Applications to [H-1-N-15]-ubiquitin and [H-1-N-15]-perdeuterated HIV-1 protease are discussed. In the case of ubiquitin, we present a pulse sequence that reduces artifacts that arise from homonuclear (3)J(H-N-H-alpha) coupling. In the case of the protease, we show that relaxation dispersion of both H-1 and N-15 spins provides a more comprehensive picture of slow backbone dynamics than does the relaxation dispersion of either spin alone. We also compare the relative merits of H-1 versus N-15 transverse relaxation measurements and note the benefits of using a perdeuterated protein to measure the relaxation dispersion of both spin types.
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页码:243 / 248
页数:6
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