Blommers M J, Lucasius C B, Kateman G, Kaptein R
Bijvoet Center, University of Utrecht, The Netherlands.
Biopolymers. 1992 Jan;32(1):45-52. doi: 10.1002/bip.360320107.
The solution structure of the photodimer cis,syn-dUp[]dT is derived with the aid of the genetic algorithm. The conformational space available for the molecule is sampled efficiently using the computer program DENISE and tested against a set of constraints available from nmr experiments. The dominant conformation in solution found with this approach can be described by the following combinations of sugar-phosphate backbone torsion angles: epsilon(t), zeta(t), alpha(+), beta(-ac), and gamma(t). The conformation of the sugars and glycosidic torsion angles are S type and syn, respectively. The cyclobutane ring and pyrimidines are puckered. In addition, other conformations that exist in equilibrium with the first are found. It is concluded that the cyclobutane-pyrimidine system is rigid, whereas the sugar-phosphate backbone is flexible. The solution structures are compared with the crystal structure of the strongly related cyano-ethyl ester of cis,syn-dTp[]dT.
借助遗传算法推导了光二聚体顺式、反式-dUp[]dT的溶液结构。使用计算机程序DENISE对分子可用的构象空间进行有效采样，并根据核磁共振实验得到的一组约束条件进行测试。用这种方法在溶液中发现的主要构象可用以下糖-磷酸主链扭转角的组合来描述：ε(t)、ζ(t)、α(+)、β(-ac)和γ(t)。糖的构象和糖苷扭转角分别为S型和反式。环丁烷环和嘧啶呈褶皱状。此外，还发现了与第一种构象处于平衡状态的其他构象。得出的结论是，环丁烷-嘧啶体系是刚性的，而糖-磷酸主链是柔性的。将溶液结构与顺式、反式-dTp[]dT的强相关氰基乙酯的晶体结构进行了比较。
