Mutagenic potential of DNA glycation: miscoding by (R)- and (S)-N2-(1-carboxyethyl)-2'-deoxyguanosine.
Mutagenic potential of DNA glycation: miscoding by (R)- and (S)-N2-(1-carboxyethyl)-2'-deoxyguanosine.
复制标题
DNA 糖化的潜在诱变性：(R)- 和 (S)-N2-(1-羧乙基)-2-脱氧鸟苷的错误编码。
DOI：
10.1021/bi901924b
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发表时间：
2010
期刊：
影响因子：
2.9
通讯作者：
Termini,John
中科院分区：
文献类型：
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作者：
Wuenschell,GeraldE;Tamae,Daniel;Cercillieux,Angelique;Yamanaka,Rio;Yu,Calvin;Termini,John
由肥胖和代谢疾病的并发症引起的循环葡萄糖升高可导致蛋白质、脂质和DNA的晚期糖基化终产物（AGEs）的积累。DNA−AGEs的形成具有特别重要的意义，因为这些加合物可能导致遗传不稳定性和与代谢疾病相关的癌症风险升高。主要的DNA−AGE，N2-（1-羧乙基）-2′-脱氧鸟苷（CEdG），在聚合物和单体水平上都是RandS异构体的混合物。为了检查这种加合物的错误编码潜力，合成了用（R）-和（S）-CEdG以及相应的三磷酸（R）-和（S）-CEdGTP取代的寡核苷酸，并使用稳态动力学方法检查了每种立体异构体的碱基配对偏好。当使用Klenow（Kf−）或Thermus aquaticus（Taq）聚合酶时，嘌呤dNTP优先与模板CEdG相对掺入。Kf−聚合酶优先掺入dGTP，而Taq则表现出对dATP的偏好。Kf−掺入嘌呤的效率更高，与Risomer相反，但Taq更倾向于S isomer。（R）-和（S）-CEdGTP的掺入仅发生在dC的对面，并且以相同的效率被Kf−催化。仅在Risomer中观察到引物从3′-末端CEdG延伸。这些数据表明，CEdG可能是导致观察到的由暴露于升高的葡萄糖或其α-乙醛分解产物甲基乙二醛诱导的G颠换模式的加合物。结果表明，模板DNA中的CEdG和相应的三磷酸盐在复制过程中具有不同的顺/反构象，从而影响碱基配对偏好。对CEdG诱导的体内致突变作用的意义进行了讨论。
Elevated circulating glucose resulting from complications of obesity and metabolic disease can result in the accumulation of advanced glycation end products (AGEs) of proteins, lipids, and DNA. The formation of DNA−AGEs assumes particular importance as these adducts may contribute to genetic instability and elevated cancer risk associated with metabolic disease. The principal DNA−AGE,N2-(1-carboxyethyl)-2′-deoxyguanosine (CEdG), is formed as a mixture ofRandSisomers at both the polymer and monomer levels. In order to examine the miscoding potential of this adduct, oligonucleotides substituted with (R)- and (S)-CEdG and the corresponding triphosphates (R)- and (S)-CEdGTP were synthesized, and base-pairing preferences for each stereoisomer were examined using steady-state kinetic approaches. Purine dNTPs were preferentially incorporated opposite template CEdG when either the Klenow (Kf−) orThermus aquaticus(Taq) polymerases were used. The Kf−polymerase preferentially incorporated dGTP, whereas Taq demonstrated a bias for dATP. Kf−incorporated purines opposite theRisomer with greater efficiency, but Taq favored theSisomer. Incorporation of (R)- and (S)-CEdGTP only occurred opposite dC and was catalyzed by Kf−with equal efficiencies. Primer extension from a 3′-terminal CEdG was observed only for theRisomer. These data suggest CEdG is the likely adduct responsible for the observed pattern of G transversions induced by exposure to elevated glucose or its α-oxoaldehyde decomposition product methylglyoxal. The results imply that CEdG within template DNA and the corresponding triphosphate possess differentsyn/anticonformations during replication which influence base-pairing preferences. The implications for CEdG-induced mutagenesisin vivoare discussed.