Clore G M, Gronenborn A M, Tjandra N
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5, Bethesda, Maryland 20892-0520, USA.
J Magn Reson. 1998 Mar;131(1):159-62. doi: 10.1006/jmre.1997.1345.
Residual dipolar couplings arising from small degrees of alignment of molecules in a magnetic field provide unique long-range structural information. The potential of this approach for structure refinement has recently been demonstrated for a protein-DNA complex in which the magnetic susceptibility tensor was axially symmetric. For most macromolecules and macromolecular complexes, however, axial symmetry cannot be assumed. Moreover, the presence of significant rhombicity will clearly affect the accuracy of the resulting coordinates. In this Communication we present a simple calculational strategy that makes use of simulated annealing refinement against the residual dipolar couplings in combination with a grid search, to simultaneously refine the structures and ascertain the magnitude of the axial and rhombic components of the tensor.
由分子在磁场中的小程度排列产生的剩余偶极耦合提供了独特的远程结构信息。这种方法用于结构优化的潜力最近已在一个蛋白质 - DNA 复合物中得到证明，其中磁化率张量是轴对称的。然而，对于大多数大分子和大分子复合物，不能假设其具有轴对称性。此外，显著的菱形度的存在显然会影响所得坐标的准确性。在本通讯中，我们提出了一种简单的计算策略，该策略利用针对剩余偶极耦合的模拟退火优化并结合网格搜索，来同时优化结构并确定张量的轴向和菱形分量的大小。
