Brandl M, Meyer M, Sühnel J
Biocomputing, Institut für Molekulare Biotechnologie, Jena, Germany.
J Biomol Struct Dyn. 2001 Feb;18(4):545-55. doi: 10.1080/07391102.2001.10506687.
Geometries and interaction energies of unusual UU and AA base pairs with one standard hydrogen bond (H-bond) and additional C-H...O or C-H...N contacts have been determined by quantum-chemical methods taking into account electron correlation. Whereas the C-H bond length in the UU C-H...O contact increases upon complex formation (H-bond pattern), the C-H bond of the AA C-H....N interaction is shortened (anti-H-bond pattern). The same properties are found for model complexes between U or A and formaldehyde that have intermolecular C-H...acceptor contacts but no standard H-bonds. Both the C-H...acceptor H-bond and anti-H-bond interactions are attractive. A possible influence of the donor CH group charge distribution on the interaction pattern is discussed.
通过考虑电子相关的量子化学方法，已确定了具有一个标准氢键（H键）以及额外C-H...O或C-H...N接触的异常UU和AA碱基对的几何结构和相互作用能。在UU的C-H...O接触中，形成复合物时（H键模式）C-H键长度增加，而AA的C-H....N相互作用中的C-H键则缩短（反H键模式）。在U或A与甲醛之间具有分子间C-H...受体接触但无标准H键的模型复合物中也发现了相同的性质。C-H...受体H键和反H键相互作用均具有吸引力。文中讨论了供体CH基团电荷分布对相互作用模式可能产生的影响。
