Mahendrasingam A, Rhodes N J, Goodwin D C, Nave C, Pigram W J, Fuller W, Brahms J, Vergne J
Nature. 1983 Feb 10;301(5900):535-7. doi: 10.1038/301535a0.
The synthetic polynucleotide poly[d(AT)].poly[d(AT)] is of interest in studies of the relationship between nucleic acid structure and function. In particular, A + T-rich regions in DNA double helices have been invoked as centres for controlling the transcription of genetic information. Here we describe conditions for observing by X-ray fibre diffraction the A, B, C and D conformations of Na-poly[d(AT)].poly[d(AT)], and for inducing transitions between these conformations. The D form emerges as a particularly stable conformation; once assumed, it persists over a wide range of variation in the relative humidity of the fibre environment. Further, while transitions between the B and D conformations are readily reversible, transitions between A and D are much more complex.
合成多核苷酸聚[d(AT)]·聚[d(AT)]在核酸结构与功能关系的研究中备受关注。特别是，DNA双螺旋中富含A+T的区域已被认为是控制遗传信息转录的中心。在此，我们描述了通过X射线纤维衍射观察钠-聚[d(AT)]·聚[d(AT)]的A、B、C和D构象以及诱导这些构象之间转变的条件。D构象表现为一种特别稳定的构象；一旦形成，它在纤维环境相对湿度的广泛变化范围内持续存在。此外，虽然B和D构象之间的转变很容易逆转，但A和D之间的转变则要复杂得多。
