Dearing A, Weiner P, Kollman P A
Nucleic Acids Res. 1981 Mar 25;9(6):1483-97. doi: 10.1093/nar/9.6.1483.
Previous workers have reported that proflavine and acridine orange form various structurally different complexes with the dinucleoside phosphates rCpG and dCpG, with uniform C3'-endo and mixed C3'-endo (3'-5') C2'-endo sugar puckers being observed. We present theoretical calculations, based on the method of molecular mechanics, which support the experimental observations. The results suggest that the mixed C3'-edo (3'-5') C2'-endo pucker conformation isi intrinsically more stable than the uniform C3'-endo conformation, but that the additional stabilisation gained from specific, hydrogen bonding, interactions between nucleic acid and solvent, or intramolecularly within the nucleic acid, can lead to the adoption of the latter conformation, or of variants between the two. The role played by hydrogen bonding between amino-groups and nucleic acid phosphate appears more subtle than previously supposed.
先前的研究人员报告说,原黄素和吖啶橙与二核苷磷酸酯rCpG和dCpG形成各种结构不同的复合物,观察到具有均匀的C3'-内型和混合的C3'-内型(3'-5')C2'-内型糖折叠。我们基于分子力学方法进行了理论计算,这些计算支持了实验观察结果。结果表明,混合的C3'-内型(3'-5')C2'-内型折叠构象本质上比均匀的C3'-内型构象更稳定,但是从核酸与溶剂之间的特定氢键相互作用或核酸分子内获得的额外稳定性可以导致采用后一种构象或两者之间的变体。氨基与核酸磷酸之间的氢键所起的作用似乎比以前认为的更为微妙。