TY - JOUR
T1 - Longitudinal and transverse 1H-15N dipolar/15N chemical shift anisotropy relaxation interference
T2 - Unambiguous determination of rotational diffusion tensors and chemical exchange effects in biological macromolecules
AU - Kroenke, Christopher D.
AU - Loria, J. Patrick
AU - Lee, Larry K.
AU - Rance, Mark
AU - Palmer, Arthur G.
PY - 1998/8/12
Y1 - 1998/8/12
N2 - High-resolution proton-detected heteronuclear correlation NMR spectroscopy allows the measurement of 15N spin relaxation rates at multiple sites throughout a biological macromolecule. The rate constants are determined by stochastic internal motions on time scales of picoseconds to nanoseconds, overall molecular rotational diffusion on time scales of nanoseconds, and chemical exchange rates on time scales of microseconds to milliseconds. A new method has been developed for distinguishing the contributions of chemical exchange from the contributions due to anisotropic rotational diffusion by measuring both longitudinal and transverse interference between the 1H-15N dipolar and 15N chemical shift anisotropy interactions. The spectroscopic experiment for measuring the longitudinal cross-correlation rate constant for 1H-15N dipolar/15N chemical shift anisotropy interference is based on the approach for measuring the transverse cross-correlation rate constant (Tjandra, N.; Szabo, A.; Bax, A. J. Am. Chem. Soc. 1996, 118, 6986-6991) but incorporates a novel method for averaging the relaxation rates of longitudinal magnetization and two spin order. Application of this technique to Escherichia coli ribonuclease H affords an improved description of rotational diffusion anisotropy and permits a more accurate assessment of chemical exchange in this molecule. The results definitively demonstrate that amino acid residues K60 and W90 are subject to conformational exchange processes, whereas increased transverse relaxation rates for residues in the helix α(D) arise from anisotropic rotational diffusion.
AB - High-resolution proton-detected heteronuclear correlation NMR spectroscopy allows the measurement of 15N spin relaxation rates at multiple sites throughout a biological macromolecule. The rate constants are determined by stochastic internal motions on time scales of picoseconds to nanoseconds, overall molecular rotational diffusion on time scales of nanoseconds, and chemical exchange rates on time scales of microseconds to milliseconds. A new method has been developed for distinguishing the contributions of chemical exchange from the contributions due to anisotropic rotational diffusion by measuring both longitudinal and transverse interference between the 1H-15N dipolar and 15N chemical shift anisotropy interactions. The spectroscopic experiment for measuring the longitudinal cross-correlation rate constant for 1H-15N dipolar/15N chemical shift anisotropy interference is based on the approach for measuring the transverse cross-correlation rate constant (Tjandra, N.; Szabo, A.; Bax, A. J. Am. Chem. Soc. 1996, 118, 6986-6991) but incorporates a novel method for averaging the relaxation rates of longitudinal magnetization and two spin order. Application of this technique to Escherichia coli ribonuclease H affords an improved description of rotational diffusion anisotropy and permits a more accurate assessment of chemical exchange in this molecule. The results definitively demonstrate that amino acid residues K60 and W90 are subject to conformational exchange processes, whereas increased transverse relaxation rates for residues in the helix α(D) arise from anisotropic rotational diffusion.
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U2 - 10.1021/ja980832l
DO - 10.1021/ja980832l
M3 - Article
AN - SCOPUS:0032511359
SN - 0002-7863
VL - 120
SP - 7905
EP - 7915
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 31
ER -