Peter H, Csanády G
Institut für Arbeitsphysiologie, Universität Dortmund, Federal Republic of Germany.
Arch Toxicol. 1990;64(6):504-5. doi: 10.1007/BF01977635.
The reactivity of aliphatic epoxides like ethylene oxide, chloroethylene oxide or propylene oxide towards N-3 and N-7 in both purine bases was calculated by the MNDO method and correlated with their HOMO coefficients. A greater chemical susceptibility of the N-3 position in both purines to aliphatic epoxides when compared with the N-7 position was found. On this background the preference of aliphatic epoxides for the N-7 position of guanine in DNA was explained by the existence of intramolecular hydrogen bonds in adenine and guanine and the steric orientation of the N-3 (minor groove) and N-7 (major groove) positions of both purines in alpha-helical DNA.
采用MNDO方法计算了环氧乙烷、氯环氧乙烷或环氧丙烷等脂肪族环氧化物与两种嘌呤碱基中N-3和N-7的反应活性，并将其与它们的最高占据分子轨道（HOMO）系数相关联。结果发现，与N-7位相比，两种嘌呤中N-3位对脂肪族环氧化物的化学敏感性更高。在此背景下，通过腺嘌呤和鸟嘌呤中分子内氢键的存在以及α-螺旋DNA中两种嘌呤的N-3（小沟）和N-7（大沟）位置的空间取向，解释了脂肪族环氧化物对DNA中鸟嘌呤N-7位的偏好。
