Sheth A, Ravikumar M, Hosur R V, Govil G, Miles H T
Biochem Biophys Res Commun. 1987 Apr 14;144(1):26-34. doi: 10.1016/s0006-291x(87)80470-9.
Two dimensional (2D) FT-NMR investigations have been carried out on the self-complementary dodecanucleotide d-CTCGAGCTCGAG, which has cleavage sites for the restriction enzyme Xho I (between C and T). The central TCG portion is also known to show a preference for DNAase activity. Complete resonance assignments have been obtained for the non-exchangeable sugar and base protons of the oligonucleotide. Information regarding sugar geometries, glycosidic torsion angles and other structural parameters has been obtained from the relative intensities of the cross peaks in the COSY and NOESY spectra. The results indicate that deoxyribose rings of C1 and C7 adopt a conformation different from the remaining sugars in the double helical oligonucleotide. The central TCG portion also exhibits variations in the backbone structure. The base stacking in the double helix shows interesting sequence dependent effects suggesting that the sequence effects are not localised to nearest neighbours but extended over longer stretches.
已对自互补十二聚体核苷酸d-CTCGAGCTCGAG进行了二维（2D）傅里叶变换核磁共振（FT-NMR）研究，该核苷酸具有限制性内切酶Xho I的切割位点（在C和T之间）。已知中央的TCG部分对DNA酶活性也有偏好。已获得该寡核苷酸不可交换糖和碱基质子的完整共振归属。从COSY和NOESY谱中交叉峰的相对强度获得了有关糖几何形状、糖苷扭转角和其他结构参数的信息。结果表明，C1和C7的脱氧核糖环采取了与双螺旋寡核苷酸中其余糖不同的构象。中央的TCG部分在主链结构上也表现出变化。双螺旋中的碱基堆积显示出有趣的序列依赖性效应，这表明序列效应并非局限于最近邻，而是延伸到更长的片段。
