Formation of Deoxyguanosine Cross-Links from Calf Thymus DNA Treated with Acrolein and 4-Hydroxy-2-nonenal
Formation of Deoxyguanosine Cross-Links from Calf Thymus DNA Treated with Acrolein and 4-Hydroxy-2-nonenal
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DOI：
10.1021/tx100179g
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发表时间：
2010-11-01
影响因子：
4.1
通讯作者：
Rizzo, Carmelo J.
中科院分区：
文献类型：
--
作者：
Kozekov, Ivan D.;Turesky, Robert J.;Rizzo, Carmelo J.
丙烯醛（AC）和4-羟基-2-壬烯醛（HNE）是内源性双亲电体，由多不饱和脂肪酸氧化产生。AC也在香烟烟雾和汽车尾气中以高浓度存在。这些反应性α，β-不饱和醛（烯醛）共价修饰核酸，形成环外加合物，其中三碳羟基丙单元桥接脱氧鸟苷（dG）的N1和N-2位置。这些烯醛的双官能性质允许它们与第二亲核基团反应并形成DNA交联。这些交联的烯醛加合物可能导致AC和HNE的遗传毒性作用。我们已经开发了一种灵敏的质谱方法来检测这些烯醛在小牛胸腺DNA（CT DNA）处理AC或HNE的交联加合物。AC和HNE交联加合物通过稳定同位素稀释法测量，采用线性四极离子阱质谱仪并在MS 3或MS 4扫描阶段进行连续反应监测。当测定50 μ g DNA时，交联加合物的定量下限类似于每10（8）个DNA碱基1个加合物。交联的加合物以类似于用任一烯醛处理的CT DNA中单体1，N-2-dG加合物水平的1-2%的水平发生。
Acrolein (AC) and 4-hydroxy-2-nonenal (HNE) are endogenous bis-electrophiles that arise from the oxidation of polyunsaturated fatty acids. AC is also found in high concentrations in cigarette smoke and automobile exhaust. These reactive alpha,beta-unsaturated aldehyde (enal) covalently modify nucleic acids, to form exocyclic adducts, where the three-carbon hydroxypropano unit bridges the N1 and N-2 positions of deoxyguanosine (dG). The bifunctional nature of these enals allows them to undergo reaction with a second nucleophilic group and form DNA cross-links. These cross-linked enal adducts are likely to contribute to the genotoxic effects of both AC and HNE. We have developed a sensitive mass spectrometric method to detect cross-linked adducts of these enals in calf thymus DNA (CT DNA) treated with AC or HNE. The AC and HNE cross-linked adducts were measured by the stable isotope dilution method, employing a linear quadrupole ion trap mass spectrometer and consecutive reaction monitoring at the MS3 or MS4 scan stage. The lower limit of quantification of the cross-linked adducts is similar to 1 adduct per 10(8) DNA bases, when 50 mu g of DNA is assayed. The cross-linked adducts occur at levels that are similar to 1-2% of the levels of the monomeric 1,N-2-dG adducts in CT DNA treated with either enal.