The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
J Am Chem Soc. 2011 Jun 15;133(23):9124-8. doi: 10.1021/ja203839e. Epub 2011 May 24.
We report label-free electrical detections of chemically modified nucleobases in a DNA using a nucleotide-sized electrode gap. We found that methyl substitution contributes to increase the tunneling conductance of deoxycytidines, which was attributed to a shift of the highest occupied molecular orbital level closer to the electrode Fermi level by methylation. We also demonstrate statistical identifications of methylcytosines in an oligonucleotide by tunneling current. This result suggests a possible use of the transverse electron-transport method for a methylation level analysis.
我们报告了在核苷酸大小的电极间隙中使用无标记电检测化学修饰的核苷酸碱基。我们发现甲基取代有助于增加脱氧胞嘧啶的隧道电导，这归因于甲基化使最高占据分子轨道能级更接近电极费米能级。我们还通过隧道电流证明了寡核苷酸中甲基胞嘧啶的统计鉴定。该结果表明横向电子输运方法可用于分析甲基化水平。
