Katahira M, Sugeta H, Kyogoku Y
Institute for Protein Research, Osaka University, Japan.
Nucleic Acids Res. 1990 Feb 11;18(3):613-8. doi: 10.1093/nar/18.3.613.
The conformations of double-stranded d(GGAAATTTCC) x 2, d(GGTTTAAACC) x 2, d(CGCAAAAAAGCG)d(CGCTTTTTTGCG) and d(GCATTTTGAAACG)d(CGTTTCAAAATGC) have been studied by NMR spectroscopy. Analyses of cross peaks in NOESY spectra between the H2 of an adenine and the H1' of a deoxyribose in the 3'-neighbouring residue on the complementary strand revealed that the minor groove of the oligo(dA) tract is compressed gradually from 5' to 3' in each duplex. In view of this gradual compression of the minor groove along the oligo(dA) tract, it can be understood clearly why d(GGAAATTTCC)n x 2 and d(GAAAATTTTC)n x 2 are bent, and d(GGTTTAAACC)n x 2 and d(GTTTTAAAAC)n x 2 are not bent. The relative extents of bending of a series of d(AjN10-j)nd(N10-jTj)n sequences can also be understood systematically. Additionally, it was found that the TA step disturbed the compression of the minor groove of the oligo(dA) tract to some extent.
已通过核磁共振光谱法研究了双链d(GGAAATTTCC)×2、d(GGTTTAAACC)×2、d(CGCAAAAAAGCG)d(CGCTTTTTTGCG)和d(GCATTTTGAAACG)d(CGTTTCAAAATGC)的构象。对互补链上3'相邻残基中腺嘌呤的H2与脱氧核糖的H1'之间的NOESY谱中的交叉峰分析表明,在每个双链体中,寡聚(dA)区段的小沟从5'到3'逐渐压缩。鉴于沿着寡聚(dA)区段小沟的这种逐渐压缩,可以清楚地理解为什么d(GGAAATTTCC)n×2和d(GAAAATTTTC)n×2是弯曲的,而d(GGTTTAAACC)n×2和d(GTTTTAAAAC)n×2不是弯曲的。一系列d(AjN10-j)nd(N10-jTj)n序列的相对弯曲程度也可以系统地理解。此外,还发现TA步在一定程度上干扰了寡聚(dA)区段小沟的压缩。