Characterization of Interstrand DNA鈥揇NA Cross-Links Using the 伪-Hemolysin Protein Nanopore

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• 作者：Xinyue Zhang ; Nathan E. Price ; Xi Fang ; Zhiyu Yang ; Li-Qun Gu ; Kent S. Gates
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：December 22, 2015
• 年：2015
• 卷：9
• 期：12
• 页码：11812-11819
• 全文大小：503K
• ISSN：1936-086X

文摘

Nanopore-based sensors have been studied extensively as potential tools for DNA sequencing, characterization of epigenetic modifications such as 5-methylcytosine, and detection of microRNA biomarkers. In the studies described here, the 伪-hemolysin protein nanopore embedded in a lipid bilayer was used for the detection and characterization of interstrand cross-links in duplex DNA. Interstrand cross-links are important lesions in medicinal chemistry and toxicology because they prevent the strand separation that is required for read-out of genetic information from DNA in cells. In addition, interstrand cross-links are used for the stabilization of duplex DNA in structural biology and materials science. Cross-linked DNA fragments produced unmistakable current signatures in the nanopore experiment. Some cross-linked substrates gave irreversible current blocks of >10 min, while others produced long current blocks (10鈥?00 s) before the double-stranded DNA cross-link translocated through the 伪-hemolysin channel in a voltage-driven manner. The duration of the current block for the different cross-linked substrates examined here may be dictated by the stability of the duplex region left in the vestibule of the nanopore following partial unzipping of the cross-linked DNA. Construction of calibration curves measuring the frequency of cross-link blocking events (1/蟿_on) as a function of cross-link concentration enabled quantitative determination of the amounts of cross-linked DNA present in samples. The unique current signatures generated by cross-linked DNA in the 伪-HL nanopore may enable the detection and characterization of DNA cross-links that are important in toxicology, medicine, and materials science.