Hosur R V, Ravikumar M, Chary K V, Sheth A, Govil G, Zu-Kun T, Miles H T
FEBS Lett. 1986 Sep 1;205(1):71-6. doi: 10.1016/0014-5793(86)80868-7.
A new approach based on the correlated spectroscopy (COSY) in 2D NMR has been described for determination of sugar geometries in oligonucleotides. Under the usual low resolution conditions employed in COSY, the intensities of cross peaks depend on the magnitudes of coupling constants. There are five vicinal coupling constants in a deoxyribose ring which are sensitive to the sugar geometry. The presence, absence and rough comparison of relative intensities of COSY cross peaks arising from such coupling constants enable one to fix the sugar conformation to a fair degree of precision. The methodology has been applied to d-GAATTCGAATTC. It is observed that ten out of the twelve nucleotide units in this sequence exhibit a rare O1'-endo geometry. The EcoRI cleavage sites (between G and A) in the dodecanucleotide show an interesting variation in the conformation with the two sugars attached to the Gs acquiring a geometry between C2'-endo and C4'-endo.
已描述了一种基于二维核磁共振相关光谱法（COSY）的新方法，用于确定寡核苷酸中糖的几何结构。在COSY通常采用的低分辨率条件下，交叉峰的强度取决于耦合常数的大小。脱氧核糖环中有五个邻位耦合常数，它们对糖的几何结构敏感。由这些耦合常数产生的COSY交叉峰相对强度的有无及粗略比较，能使人们在相当精确的程度上确定糖的构象。该方法已应用于d-GAATTCGAATTC。观察到该序列中十二个核苷酸单元中的十个呈现出罕见的O1'-内型几何结构。十二聚体中的EcoRI切割位点（在G和A之间）在构象上表现出有趣的变化，与G相连的两个糖的几何结构介于C2'-内型和C4'-内型之间。
