Hobza P, Sandorfy C
Proc Natl Acad Sci U S A. 1983 May;80(10):2859-60. doi: 10.1073/pnas.80.10.2859.
Ab initio self-consistent field calculations with 4-31G and STO-3G basis sets show that Na+ are able to damage the H bonds in the formamidine . formamide complex, modeling the adenine . thymine base pair (both H bonds in the complex investigated are the same as in adenine . thymine). If a water molecule is placed between the complex and Na+, the H bonds of the model are fully protected. Covalent as well as noncovalent binding of polycyclic aromatic hydrocarbons to nucleic acids should decrease the local concentration of water as a result of the insertion of the hydrophobic hydrocarbon into the DNA and thereby increase the exposure of the DNA H bonds to Na+ attack. Thus, Na+ reaching the base pair could provoke or interfere with cell division.
采用4-31G和STO-3G基组进行的从头算自洽场计算表明，Na⁺能够破坏甲脒.甲酰胺复合物中的氢键，该复合物模拟了腺嘌呤.胸腺嘧啶碱基对（所研究复合物中的两个氢键与腺嘌呤.胸腺嘧啶中的相同）。如果在复合物和Na⁺之间放置一个水分子，模型的氢键会得到充分保护。多环芳烃与核酸的共价和非共价结合，由于疏水性烃插入DNA中，会降低局部水浓度，从而增加DNA氢键受到Na⁺攻击的暴露程度。因此，到达碱基对的Na⁺可能引发或干扰细胞分裂。
