Electrochemical behavior of 7-deazaguanine- and 7-deazaadenine-modified DNA at the hanging mercury drop electrode
Electrochemical behavior of 7-deazaguanine- and 7-deazaadenine-modified DNA at the hanging mercury drop electrode
复制标题
7-脱氮鸟嘌呤和 7-脱氮腺嘌呤修饰的 DNA 在悬挂汞滴电极上的电化学行为
DOI：
10.1007/s00706-015-1584-7
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
M. Fojta
中科院分区：
文献类型：
--
作者：
Zdenka Dudová;J. Špaček;M. Tomasko;L. Havran;Hana Pivoňková;M. Fojta
利用合成的天然核苷酸类似物和/或其与外部氧化还原活性基团的结合物进行DNA修饰，可用于开发DNA电化学传感器或用于DNA杂交、SNP分型、DNA损伤等检测。7-地氮嘌呤(7-Dazapurines，Pu*)是天然嘌呤碱的类似物，其中N7原子被CH基团取代。Pu*碱基保留了其亲代嘌呤的Watson-Crick碱基配对(以及形成双链DNA的能力)，但不能进行Hoogsteen配对(因此不能参与三链或四链DNA结构)。以前，我们研究了DNA片段中Pu*残基在碳电极上的电化学氧化(在Pu*脱氧核苷三磷酸盐存在下通过聚合酶链法制备)，并报道了7-去氮鸟嘌呤(G*)和7-去氮腺嘌呤(A*)的氧化电位分别显著低于天然鸟嘌呤(G)和腺嘌呤(A)。在这项工作中，我们研究了G*或A*修饰的DNA在悬汞电极(HMDE)上的法拉第和张量响应。而A*在HMDE处被还原，产生一个与天然A相似的不可逆阴极峰，而G*没有产生任何类似于鸟嘌呤所致的峰G的峰，这与G*中相应的氧化还原位置的损失是一致的。A*修饰的DNA与未修饰的DNA的响应相对相似(尽管我们观察到张量峰电流有一定的差异)。G*取代G的作用更为明显，表现为鸟嘌呤引起的峰减小，胞嘧啶和腺嘌呤还原引起的峰CA降低，以及DNA张量信号的形状明显改变，表明吸附/解吸过程发生了改变。虽然A*取代A会导致带负电的HMDE表面DNA双链的某些不稳定(定性上与相同DNA双链在溶液中的熔化温度显著降低一致)，但G*修饰的双链DNA对表面变性的敏感性明显降低。
DNA modification with synthetic analogs of natural nucleotides and/or their conjugates with external redox active groups is applied in the development of electrochemical DNA sensors or assay for DNA hybridization, SNP typing, DNA damage and so forth. 7-Deazapurines (Pu*) are analogs of natural purine bases in which N7 atom is replaced by CH group. The Pu* bases retain Watson–Crick base pairing of their parent purines (and the ability to form duplex DNA) but are incapable of Hoogsteen pairing (and thus cannot be involved in triplex or quadruples DNA structures). Previously, we studied electrochemical oxidation of Pu* residues in DNA fragments (prepared by PCR in the presence of Pu* deoxynucleoside triphosphates) at a carbon electrode and reported on significantly lower potentials of oxidation of both 7-deazaguanine (G*) and 7-deazaadenine (A*), compared to natural guanine (G) and adenine (A), respectively. In this work, we studied faradaic and tensammetric responses of G*- or A*-modified DNA on the hanging mercury drop electrode (HMDE). While A* was reduced at the HMDE, giving rise to a similar irreversible cathodic peak as the natural A, G* did not yield any peak analogous to the peak G due to guanine, in agreement with a loss of corresponding redox site in G*. Responses of DNA modified with A* were relatively similar to those of unmodified DNA (albeit we observed certain differences in tensammetric peak currents). Effects of G substitution by G* were more pronounced, being reflected in diminution of peak due to guanine, decrease of the peak CA (due to cytosine and adenine reduction) and in significantly changed shape of tensammetric DNA signals, indicating altered adsorption/desorption processes. While substitution of A by A* resulted in certain destabilization of the DNA duplex at the negatively charged HMDE surface (in qualitative agreement with significantly decreased melting temperature of the same DNA duplexes in solution), G*-modified duplex DNA displayed apparently lower susceptibility to surface denaturation.Graphical abstract
影响因子：
3
作者：
M. Jacobsen;G. Flechsig
通讯作者：
M. Jacobsen;G. Flechsig