Lam Sik Lok, Ip Lai Nang
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
J Biomol Struct Dyn. 2002 Apr;19(5):907-17. doi: 10.1080/07391102.2002.10506793.
Solution structures and base pair stacking of a self- complementary DNA hexamer d(CGTACG)(2) have been studied at 5, 10 and 15 degrees C, respectively. The stacking interactions among the center base pair steps of the DNA duplex are found to improve when the terminal base pairs became less stable due to end fraying. A new structural quantity, the stacking sum (Sigma(s)), is introduced to indicate small changes in the stacking overlaps between base pairs. The improvements in the stacking overlaps to maintain the double helical conformation are probably the cause for the observed temperature dependent structural changes in double helical DNA molecule. A detailed analysis of the helical parameters, backbone torsion angles, base orientations and sugar conformations of these structures has been performed.
分别在5℃、10℃和15℃下研究了自互补DNA六聚体d（CGTACG）（2）的溶液结构和碱基对堆积。当末端碱基对由于末端磨损而变得不太稳定时，发现DNA双链体中心碱基对步骤之间的堆积相互作用得到改善。引入了一个新的结构量，堆积总和（Σs），以表明碱基对之间堆积重叠的微小变化。堆积重叠的改善以维持双螺旋构象可能是观察到的双螺旋DNA分子中温度依赖性结构变化的原因。对这些结构的螺旋参数、主链扭转角、碱基取向和糖构象进行了详细分析。
