Water molecule contributions to proton spin-lattice relaxation in rotationally immobilized proteins.
Water molecule contributions to proton spin-lattice relaxation in rotationally immobilized proteins.
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DOI：
10.1016/j.jmr.2009.04.001
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发表时间：
2009-07
期刊：
影响因子：
--
通讯作者：
Bryant RG
中科院分区：
文献类型：
--
作者：
Goddard YA;Korb JP;Bryant RG
在154~302K温度范围内，测量了蛋白质和水合固定化牛血清白蛋白中蛋白质和水质子的自旋晶格驰豫速率，结果表明，蛋白质质子的自旋晶格驰豫速率与磁场强度呈特征幂函数关系。水中氢的同位素替代和不同温度下的研究揭示了三种类型的水分子动力学，它们对自旋-晶格弛豫色散分布有贡献。在185K，水的1H驰豫贡献来自于蛋白质结合分子的重定向，这些分子动态地从蛋白质骨架解偶联，并以洛伦兹函数为特征。在更高的温度下，结合水分子的运动可以动态地解耦或耦合到蛋白质的波动，这也是主要的贡献。地表水的平移扩散是磁性的二维扩散，在10 MHz以上的频率下起到松弛作用。用同位素替代法研究表明，水合固定化蛋白质体系中水信号的幂指数与冷冻干燥蛋白质中质子的指数在Larmor频率上相同，超过四个数量级，这意味着与水合作用有关的蛋白质结构的变化不影响1H自旋驰豫。
Spin-lattice relaxation rates of protein and water protons in dry and hydrated immobilized bovine serum albumin were measured in the range of 1H Larmor frequency from 10 kHz to 30 MHz at temperatures from 154 to 302 K. The water proton spin-lattice relaxation reports on that of protein protons, which causes the characteristic power law dependence on the magnetic field strength. Isotope substitution of deuterium for hydrogen in water and studies at different temperatures expose three classes of water molecule dynamics that contribute to the spin-lattice relaxation dispersion profile. At 185 K, a water 1H relaxation contribution derives from reorientation of protein-bound molecules that are dynamically uncoupled from the protein backbone and is characterized by a Lorentzian function. Bound water molecule motions that can be dynamically uncoupled or coupled to the protein fluctuations make dominant contributions at higher temperatures as well. Surface water translational diffusion that is magnetically two-dimensional makes relaxation contributions at frequencies above 10 MHz. It is shown using isotope substitution that the exponent of the power law of the water signal in hydrated immobilized protein systems is the same as that for protons in lyophilized proteins over four orders of magnitude in the Larmor frequency, which implies that changes in the protein structure associated with hydration do not affect the 1H spin relaxation.
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影响因子：
--
作者：
Kuntz, I D Jr;Kauzmann, W
通讯作者：
Kauzmann, W
影响因子：
2.9
作者：
Bahar, I;Erman, B;Jernigan, RL
通讯作者：
Jernigan, RL
影响因子：
3.3
作者：
LESTER, CC;BRYANT, RG
通讯作者：
BRYANT, RG
影响因子：
3.7
作者：
ALEXANDER, S
通讯作者：
ALEXANDER, S
DOI：
10.1098/rstb.1977.0032
发表时间：
1977-01-01
期刊：
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES
影响因子：
--
作者：
FRANKS, F;SYMONS, MCR;WILLIAMS, RJP
通讯作者：
WILLIAMS, RJP