ESR and ENDOR study of the guanine cation: Secondary product in 5’‐dGMP
ESR and ENDOR study of the guanine cation: Secondary product in 5’‐dGMP
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鸟嘌呤阳离子的 ESR 和 ENDOR 研究：5-dGMP 中的次级产物
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
E. Sagstuen
中科院分区：
文献类型：
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作者：
E. Hole;W. Nelson;D. Close;E. Sagstuen
先前对2 '-脱氧鸟苷-5'-单磷酸的X辐照单晶的ESR研究表明，存在被认为是由N1处的初级碱阳离子去质子化形成的自由基。本文报道了在10 K下详细的ESR和ENDOR实验的一些结果，这些结果与上述结果相矛盾。检测到的自由基之一表现出两个α-质子型耦合。数据分析表明，一种耦合是由于环外NH 2基团的可交换质子，而另一种是由于C8处键合的质子。实验自旋密度为ρ（N10）=0.33，ρ（C8）=0.18。结果同意合理以及与INDO计算的自旋密度分布的自由基由去质子化在N10的初级阳离子自由基。该自由基在升温至约200 K时是稳定的，在那里它迅速退火。
Previous ESR studies of x‐irradiated single crystals of 2’‐deoxyguanosine‐5’‐monophosphate have indicated the presence of a radical thought to be formed by deprotonation of a primary base cation at N1. In this communication are reported some results of detailed ESR and ENDOR experiments at 10 K conflicting with the above results. One of the radicals detected exhibited two α‐proton type couplings. The data analysis shows that one coupling is due to the exchangeable proton of the extra‐annular NH2 group, while the other is due to the proton bonded at C8. The experimental spin densities were ρ(N10)=0.33, and ρ(C8)=0.18. The results agree reasonably well with the INDO calculated spin density distribution of a radical formed by deprotonation at N10 of a primary cation radical. The radical is stable on warming to about 200 K where it anneals rapidly.