Lown J W, Chang D K, Debart F, Rayner B, Imbach J L
Department of Chemistry, University of Alberta, Edmonton, Canada.
J Biomol Struct Dyn. 1986 Jun;3(6):1171-87. doi: 10.1080/07391102.1986.10508493.
The consensus acceptor exon:intron junction d(CpTpApCpApGpGpT) has been synthesized by a modified phosphotriester method. The non-self complementary octamer exists in the single strand form in aqueous buffer at 20 degrees C as evidenced by temperature variable 1H-NMR and NOE measurements. The non-exchangeable proton assignments were secured using a combination of techniques including two-dimensional COSY, NOESY and the double quantum technique 1H-1H-INADEQUATE as well as inversion recovery T1 experiments. The new technique of 31P-1H shift correlation is particularly valuable in removing certain ambiguities in the sugar proton assignments. Characteristic chemical shifts for the base protons which are determined by their immediate molecular environments are also useful in assignments. The consensus acceptor exon:intron junction adopts a random coil conformation in solution under the experimental conditions employed.
内含子连接序列d（CpTpApCpApGpGpT）已通过改良的磷酸三酯法合成。通过变温1H-NMR和NOE测量证明，这种非自身互补的八聚体在20℃的水性缓冲液中以单链形式存在。使用包括二维COSY、NOESY和双量子技术1H-1H-INADEQUATE以及反转恢复T1实验等多种技术组合确定了不可交换质子的归属。31P-1H位移相关的新技术在消除糖质子归属中的某些模糊性方面特别有价值。由其直接分子环境决定的碱基质子的特征化学位移在归属中也很有用。在所采用的实验条件下，共有受体外显子：内含子连接序列在溶液中采用无规卷曲构象。
