Fazakerley G V, Sowers L C, Eritja R, Kaplan B E, Goodman M F
Departement de Biologie, Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette, France.
Biochemistry. 1987 Sep 8;26(18):5641-6. doi: 10.1021/bi00392a009.
A heteroduplex containing the mismatch 2-aminopurine (AP)-adenine has been synthesized and studied by proton NMR. The mismatch was incorporated into the sequence d[CGG(AP)GGC].d-(GCCACCG). One-dimensional nuclear Overhauser effect measurements in H2O and two-dimensional nuclear Overhauser effect spectra in D2O show AP.A base pairs in a wobble structure in which both bases are in the anti conformation. The adenine is stacked well in the helix, but the helix twist between the adenine and neighboring cytosine in the 3' direction is unusually small. As a result, the aminopurine on the opposite strand is somewhat pushed out of the helix. From the measurements of the imino proton line widths, the two adjacent G.C base pairs are not found to be significantly destabilized by the presence of the purine-purine wobble pair.
一种含有错配物2-氨基嘌呤（AP）-腺嘌呤的异源双链体已被合成，并通过质子核磁共振进行了研究。该错配物被掺入序列d[CGG(AP)GGC].d-(GCCACCG)中。在H2O中进行的一维核Overhauser效应测量以及在D2O中进行的二维核Overhauser效应光谱表明，AP.A碱基对呈摆动结构，其中两个碱基均处于反式构象。腺嘌呤在螺旋中堆积良好，但在3'方向上腺嘌呤与相邻胞嘧啶之间的螺旋扭曲异常小。结果，互补链上的氨基嘌呤有点被挤出螺旋。从亚氨基质子线宽的测量结果来看，未发现两个相邻的G.C碱基对因嘌呤-嘌呤摆动对的存在而显著不稳定。
