Katahira M, Sugeta H, Kyogoku Y, Fujii S, Fujisawa R, Tomita K
Institute for Protein Research, Osaka University, Japan.
Nucleic Acids Res. 1988 Sep 12;16(17):8619-32. doi: 10.1093/nar/16.17.8619.
The resonances of the imino protons and all of the non-exchangeable protons (except for H5'/H5'') of d(CGCAAAAAAGCG)d(CGCTTTTTTGCG) have been assigned by means of one- and two-dimensional NMR spectroscopies. Qualitative analyses showed that the overall structure is of the B-form, but local conformational deviations exist. The NOEs between the imino protons of thymines and H2 of adenines suggest that the A-T base pairs are propeller-twisted to almost the same degree as in crystals. A remarkable chemical shift of H1' was observed for the residue located just before the oligo(dA)oligo(dT) tract, suggesting the presence of conformational discontinuity at the junctions between the oligo(dA)oligo(dT) tract and the other portions. Analyses of cross peaks in NOESY spectra between H2 of adenines and H1' of the 3'-neighbouring residues on the complementary strand revealed that the minor groove of the oligo(dA)oligo(dT) tract is narrow and compressed gradually, from 5' to 3', along the tract.
通过一维和二维核磁共振光谱法已对d(CGCAAAAAAGCG)d(CGCTTTTTTGCG)的亚氨基质子以及所有非交换质子(H5'/H5''除外)的共振进行了归属。定性分析表明,整体结构为B型,但存在局部构象偏差。胸腺嘧啶亚氨基质子与腺嘌呤H2之间的核Overhauser效应(NOE)表明,A-T碱基对的螺旋桨扭曲程度与晶体中几乎相同。在紧邻寡聚(dA)寡聚(dT)片段之前的残基处观察到H1'有显著的化学位移,这表明在寡聚(dA)寡聚(dT)片段与其他部分的连接处存在构象不连续性。对互补链上腺嘌呤H2与3'-相邻残基H1'之间的NOESY光谱交叉峰的分析表明,寡聚(dA)寡聚(dT)片段的小沟狭窄,并沿该片段从5'到3'逐渐压缩。