Rachwal Phillip A, Brown Tom, Fox Keith R
School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK.
FEBS Lett. 2007 Apr 17;581(8):1657-60. doi: 10.1016/j.febslet.2007.03.040. Epub 2007 Mar 28.
We have examined the properties of intramolecular G-quadruplexes in which the G3 tracts are separated by single base loops. The most stable complex contained 1',2'-dideoxyribose in all three loops, while loops containing T and C were slightly less stable (by about 2 degrees C). Quadruplexes containing loops with single A residues were less stable by 8 degrees C for each T to A substitution. These folded sequences display similar CD spectra, which are consistent with the formation of parallel stranded complexes with double-chain reversal loops. These results demonstrate that loop sequence, and not just length, affects quadruplex stability.
我们研究了分子内G-四链体的性质，其中G3序列被单碱基环隔开。最稳定的复合物在所有三个环中都含有1',2'-二脱氧核糖，而含有T和C的环稳定性稍低（约低2摄氏度）。每个T被A取代后，含有单A残基环的四链体稳定性降低8摄氏度。这些折叠序列显示出相似的圆二色光谱，这与形成具有双链反向环的平行链复合物一致。这些结果表明，影响四链体稳定性的是环序列，而不仅仅是长度。
