Fowler C A, Tian F, Al-Hashimi H M, Prestegard J H
Complex Carbohydrate Research Center, The University of Georgia, 220 Riverbend Road, Athens, GA, 30602-4712, USA.
J Mol Biol. 2000 Dec 1;304(3):447-60. doi: 10.1006/jmbi.2000.4199.
Over the next few years, various genome projects will sequence many new genes and yield many new gene products. Many of these products will have no known function and little, if any, sequence homology to existing proteins. There is reason to believe that a rapid determination of a protein fold, even at low resolution, can aid in the identification of function and expedite the determination of structure at higher resolution. Recently devised NMR methods of measuring residual dipolar couplings provide one route to the determination of a fold. They do this by allowing the alignment of previously identified secondary structural elements with respect to each other. When combined with constraints involving loops connecting elements or other short-range experimental distance information, a fold is produced. We illustrate this approach to protein fold determination on (15)N-labeled Eschericia coli acyl carrier protein using a limited set of (15)N-(1)H and (1)H-(1)H dipolar couplings. We also illustrate an approach using a more extended set of heteronuclear couplings on a related protein, (13)C, (15)N-labeled NodF protein from Rhizobium leguminosarum.
在接下来的几年里，各种基因组计划将对许多新基因进行测序，并产生许多新的基因产物。这些产物中的许多将没有已知的功能，并且与现有蛋白质的序列同源性很低，如果有的话。有理由相信，即使在低分辨率下快速确定蛋白质折叠，也有助于功能鉴定并加快高分辨率下结构的确定。最近设计的测量残余偶极耦合的核磁共振方法为确定折叠提供了一条途径。它们通过使先前确定的二级结构元件相互对齐来实现这一点。当与涉及连接元件的环或其他短程实验距离信息的约束相结合时，就会产生一种折叠。我们使用一组有限的(^{15}N)-(^1H)和(^1H)-(^1H)偶极耦合，说明了这种用于确定蛋白质折叠的方法在(^{15}N)标记的大肠杆菌酰基载体蛋白上的应用。我们还说明了一种在相关蛋白质，即来自豌豆根瘤菌的(^{13}C)、(^{15}N)标记的NodF蛋白上使用更广泛的异核耦合集的方法。
