Chazin W J, Rance M, Chollet A, Leupin W
Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037.
Nucleic Acids Res. 1991 Oct 25;19(20):5507-13. doi: 10.1093/nar/19.20.5507.
The dodecadeoxynucleotide duplex d-(GCATTAATGC)2 has been prepared with all adenine bases replaced by 2-NH2-adenine. This modified duplex has been characterized by nuclear magnetic resonance (NMR) spectroscopy. Complete sequence-specific 1H resonance assignments have been obtained by using a variety of 2D NMR methods. Multiple quantum-filtered and multiple quantum experiments have been used to completely assign all sugar ring protons, including 5'H and 5'H resonances. The assignments form the basis for a detailed comparative analysis of the 1H NMR parameters of the modified and parent duplex. The structural features of both decamer duplexes in solution are characteristic of the B-DNA family. The spin-spin coupling constants in the sugar rings and the relative spatial proximities of protons in the bases and sugars (as determined from the comparison of corresponding nuclear Overhauser effects) are virtually identical in the parent and modified duplexes. Thus, substitution by this adenine analogue in oligonucleotides appears not to disturb the global or local conformation of the DNA duplex.
十二聚脱氧核苷酸双链体d-(GCATTAATGC)₂已被制备出来，其中所有腺嘌呤碱基都被2-氨基腺嘌呤取代。这种修饰后的双链体已通过核磁共振（NMR）光谱进行了表征。通过使用多种二维NMR方法获得了完整的序列特异性¹H共振归属。多量子滤波和多量子实验已被用于完全归属所有糖环质子，包括5'H和5'H共振。这些归属为对修饰后的双链体和母体双链体的¹H NMR参数进行详细比较分析奠定了基础。溶液中两种十聚体双链体的结构特征都是B-DNA家族的典型特征。糖环中的自旋-自旋耦合常数以及碱基和糖中质子的相对空间接近度（由相应的核Overhauser效应比较确定）在母体双链体和修饰后的双链体中几乎相同。因此，在寡核苷酸中用这种腺嘌呤类似物进行取代似乎不会干扰DNA双链体的整体或局部构象。
