THE 3-DIMENSIONAL STRUCTURE OF A DNA DUPLEX CONTAINING LOOPED-OUT BASES
THE 3-DIMENSIONAL STRUCTURE OF A DNA DUPLEX CONTAINING LOOPED-OUT BASES
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DOI：
10.1038/334082a0
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发表时间：
1988-07-07
期刊：
影响因子：
64.8
通讯作者：
SUSSMAN, JL
中科院分区：
文献类型：
--
作者：
JOSHUATOR, L;RABINOVICH, D;SUSSMAN, JL
DNA中未配对的碱基被指定为在具有重复碱基对的序列的移码突变机制中可能扮演的角色。它们也存在于准回文DNA序列中，在没有重复碱基对的突变中，通过形成单链发夹环2，3。DNA中未配对碱基的构象一直是许多热力学以及高分辨率核磁共振(核磁共振)研究的主题(见参考文献)。4)。溶液5中的核磁共振研究表明，十三聚体DNA片段d(CGCAGAATTCGCG)的双链保持不变，未配对的腺苷堆积在双链中。在结晶了这个寡核苷酸并确定了它的结构后，我们发现它在晶体中的构象接近于B-DNA双链的构象，额外的两个腺苷从双螺旋中环出，几乎不会对其余结构造成破坏。
Unpaired bases in DNA have been assigned a possible role in the mechanism of frameshift mutagenesis in sequences with repeated base pairs1. They also occur in quasipalindromic DNA sequences, which have been implicated in mutagenesis where there are no repeated base pairs, through the formation of single-stranded hairpin loops2,3. The conformation of unpaired bases in DNA has been the subject of numerous thermodynamic as well as high resolution NMR (nuclear magnetic resonance) studies (reviewed in ref. 4). The NMR studies in solution5have shown that the duplex of the tridecamer DNA fragment d(CGCAGAATTCGCG) remains intact, and that the unpaired adenosines are stacked into the duplex. Having crystallized this oligonucleotide and determined its structure, we find its conformation in the crystal is close to that of a B-DNA duplex, with the two additional adenosines looped out from the double helix and causing little disruption of the rest of the structure.