Research School of Chemistry, Australian National University, Canberra, ACT, 0200, Australia.
J Biomol NMR. 2010 Jun;47(2):143-53. doi: 10.1007/s10858-010-9416-x. Epub 2010 Apr 20.
Paramagnetic relaxation enhancements (PRE) present a powerful source of structural information in nuclear magnetic resonance (NMR) studies of proteins and protein-ligand complexes. In contrast to conventional PRE reagents that are covalently attached to the protein, the complex between gadolinium and three dipicolinic acid (DPA) molecules, Gd(DPA)(3), can bind to proteins in a non-covalent yet site-specific manner. This offers straightforward access to PREs that can be scaled by using different ratios of Gd(DPA)(3) to protein, allowing quantitative distance measurements for nuclear spins within about 15 A of the Gd(3+) ion. Such data accurately define the metal position relative to the protein, greatly enhancing the interpretation of pseudocontact shifts induced by Ln(DPA)(3) complexes of paramagnetic lanthanide (Ln(3+)) ions other than gadolinium. As an example we studied the quaternary structure of the homodimeric GCN4 leucine zipper.
顺磁弛豫增强（PRE）在蛋白质和蛋白质-配体复合物的核磁共振（NMR）研究中提供了一种强大的结构信息来源。与传统的通过共价键连接到蛋白质的 PRE 试剂不同，钆与三个二吡啶酸（DPA）分子的复合物Gd(DPA)(3)可以以非共价但特异性的方式与蛋白质结合。这为 PRE 提供了直接的途径，可以通过使用不同比例的Gd(DPA)(3)与蛋白质来进行扩展，从而可以对距离约为 15 A 内的核自旋进行定量距离测量。这些数据可以准确地定义金属相对于蛋白质的位置，极大地增强了对除钆以外的顺磁性镧系（Ln(3+)）离子的Ln(DPA)(3)配合物诱导的赝接触位移的解释。作为一个例子，我们研究了同源二聚体 GCN4 亮氨酸拉链的四级结构。
