Redox reactivity of guanyl radicals in plasmid DNA.
Redox reactivity of guanyl radicals in plasmid DNA.
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质粒 DNA 中鸟苷基的氧化还原反应性。
DOI：
10.1080/09553000010013436
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发表时间：
2001
影响因子：
2.6
通讯作者：
Ward,JF
中科院分区：
文献类型：
--
作者：
Milligan,JR;Aguilera,JA;Nguyen,JV;Ward,JF
目的以前曾有人认为，在硫氰酸根离子存在下，质粒DNA经γ射线照射后产生的产物可被大肠杆菌识别。大肠杆菌碱基切除-修复核酸内切酶甲酰氨基嘧啶-DNA N -糖基化酶（FPG），以及衍生自中间鸟苷基种类的酶。目的是表征该中间体与还原剂的反应性。材料和方法含有溴化物或硫氰酸盐的质粒DNA的水溶液（10 - 3至10 - 1 mol dm-3）和六种其他添加剂之一（叠氮化物、亚铁氰化物、碘化物、亚硝酸盐、异丙嗪、色氨酸，10 - 7 ~ 10 - 3 moldm-3）的137 Cs γ射线辐照。照射后，将质粒与FPG孵育。链断裂产量之前和之后孵育通过琼脂糖凝胶电泳在中性conditions.ResultsThe非常高的产量的FPG敏感位点的SCN -或Br -的存在下，随着浓度的增加而显着下降的所有六个添加剂，异丙嗪和色氨酸是最有效的添加剂，结论从实验结果可以估算DNA胍基自由基还原的速率常数（亚铁氰化物、亚硝酸盐、异丙嗪和色氨酸分别为5 × 10 5、2 × 10 5、10 7和10 7 dm 3 mol-1 s-1）。
PurposeIt has been previously argued that γ-irradiation of plasmid DNA in the presence of thiocyanate ions produces products recognized by the E. coli base excision-repair endonuclease formamidopyrimidine-DNA N -glycosylase (FPG), and there that derive from an intermediate guanyl radical species. The wish was to characterize the reactivity of this intermediate with reducing agents.Materials and methodsAqueous solutions of plasmid DNA containing either bromide or thiocyanate (10 -3 to 10 -1 mol dm -3) and also one of six other additives (azide, ferrocyanide, iodide, nitrite, promethazine, tryptophan, 10 -7 to 10 -3 mol dm -3) were subjected to 137 Cs γ-irradiation (662 keV). After irradiation, the plasmid was incubated with FPG. Strand break yields before and after incubation were determined by agarose gel electrophoresis under neutral conditions.ResultsThe very high yields of FPG-sensitive sites in the presence of SCN - or Br - decreased significantly with increasing concentrations of all of the six additives, with promethazine and tryptophan being the most efficient additives, and azide and iodide the least.ConclusionsFrom the results it is possible to estimate values of the rate constants for the reduction of the DNA guanyl radical (5x10 5, 2x10 5, 10 7 and 10 7 dm 3 mol -1 s -1 for ferrocyanide, nitrite, promethazine and tryptophan respectively).
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硫氰酸盐自由基损伤 DNA 的机制。
影响因子：
2.6
作者：
Milligan,JR;Aguilera,JA;Paglinawan,RA;Ward,JF
通讯作者：
Ward,JF
影响因子：
15
作者：
Melvin, T;Botchway, SW;ONeill, P
通讯作者：
ONeill, P
影响因子：
3.4
作者：
Milligan, JR;Ng, JYY;Cunningham, RP
通讯作者：
Cunningham, RP
DNA 辐射损伤的化学后果
DOI：
10.1016/b978-0-12-035417-7.50006-4
发表时间：
1993
期刊：
Advances in radiation biology
影响因子：
--
作者：
D. Becker;M. Sevilla
通讯作者：
M. Sevilla
DOI：
10.1080/09553008514550101
发表时间：
1985
期刊：
International journal of radiation biology and related studies in physics, chemistry, and medicine
影响因子：
--
作者：
P. O'Neill;P. Chapman
通讯作者：
P. O'Neill;P. Chapman