Magnetic Field Dependence of Nitrogen−Proton J Splittings in 15N-Enriched Human Ubiquitin Resulting from Relaxation Interference and Residual Dipolar Coupling
Magnetic Field Dependence of Nitrogen−Proton J Splittings in 15N-Enriched Human Ubiquitin Resulting from Relaxation Interference and Residual Dipolar Coupling
复制标题
弛豫干扰和残余偶极耦合导致富含 15N 的人类泛素中氮-质子 J 分裂的磁场依赖性
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发表时间：
1996
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影响因子：
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通讯作者：
A. Bax
中科院分区：
文献类型：
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作者：
N. Tjandra;and Stephan Grzesiek;A. Bax
在富含15n的人泛素中测量了单键1JNH偶联，频率范围为91.1至95.6 Hz。测量使用了两种不同的方法，在360,500和600mhz的1H频率下进行。当磁场强度从8.5 t增加到14 t时，1JNH分裂发生的微小变化（<0.3 Hz）可以可靠地测量。1JNH分裂对静态磁场强度的依赖源于两个来源：15N化学位移各向异性的干扰引起的动态频移和15N−1H偶极耦合弛豫机制。由抗磁性蛋白质的各向异性磁化率引起的小程度的排列引起的偶极贡献。测量数据的最佳拟合结果显示，相对于360 MHz，在600 MHz的1JNH分裂中，与方向无关的减少了0.11 Hz，与理论预测完全一致。
One-bond 1JNH couplings have been measured in 15N-enriched human ubiquitin and range from 91.1 to 95.6 Hz. Measurements have been carried out using two different methods and at 1H frequencies of 360, 500, and 600 MHz. The best method yields a precision of ca 0.02 Hz, and permits reliable measurement of the small changes (<0.3 Hz) in 1JNH splitting that occur when the magnetic field strength is increased from 8.5 to 14 T. The dependence of the 1JNH splittings on the strength of the static magnetic field originates from two sources: a dynamic frequency shift caused by interference of the 15N chemical shift anisotropy and the 15N−1H dipolar coupling relaxation mechanisms, and a dipolar contribution caused by a small degree of alignment resulting from the anisotropic magnetic susceptibility of the diamagnetic protein. Best fitting of the measured data yields an orientation-independent decrease of 0.11 Hz in the 1JNH splittings at 600 MHz relative to 360 MHz, in perfect agreement with theoretical predictions ...