Riley Scott A, Giuliani Jason R, Augustine Matthew P
Department of Chemistry, One Shields Avenue, University of California, Davis, CA 95616, USA.
J Magn Reson. 2002 Nov;159(1):82-6. doi: 10.1016/s1090-7807(02)00004-6.
The magnetic alignment of the Pseudomonas bacteriophage Pf1 is captured indefinitely in a gel of the aqueous triblock copolymer Pluronic F-127. In addition to preserving high-resolution liquids NMR spectra for dissolved solutes, the gel prevents the reorientation of the phage allowing mechanical manipulation of the angle between the axis of the phage alignment and the static magnetic field. The residual 2H quadrupolar couplings for several solutes dissolved in this material as a function of the angle Theta between the non-spinning sample tube and the static magnetic field are consistent with the value of P(2)(cosTheta)=(3cos(2)Theta-1)/2. The variable-angle correlation spectrum for these solutes is shown to separate residual quadrupolar effects from isotropic chemical shifts. Finally, the compatibility of Pluronic F-127 with NMR studies of aqueous biological macromolecules is demonstrated in a measurement of residual dipolar couplings in an 15N-labeled nucleic acid.
假单胞菌噬菌体Pf1的磁取向在三嵌段共聚物Pluronic F-127的水凝胶中被无限期捕获。除了为溶解的溶质保留高分辨率液体核磁共振谱外，该凝胶还能防止噬菌体重新取向，从而允许对噬菌体取向轴与静磁场之间的角度进行机械操纵。溶解在这种材料中的几种溶质的残余2H四极耦合作为非旋转样品管与静磁场之间角度θ的函数，与P(2)(cosθ)=(3cos(2)θ-1)/2的值一致。这些溶质的可变角度相关谱显示出能将残余四极效应与各向同性化学位移分开。最后，通过对15N标记核酸中残余偶极耦合的测量，证明了Pluronic F-127与水性生物大分子核磁共振研究的兼容性。
