title: Electrical detection of single methylcytosines in a DNA oligomer.
abstract: 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.
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Makusu
authors.initials: M
authors.lastname: Tsutsui
authors.forename: Kazuki
authors.initials: K
authors.lastname: Matsubara
authors.forename: Takahito
authors.initials: T
authors.lastname: Ohshiro
authors.forename: Masayuki
authors.initials: M
authors.lastname: Furuhashi
authors.forename: Masateru
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Tomoji
authors.initials: T
authors.lastname: Kawai
mesh_terms: D003596:Cytosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D003843:Deoxycytidine Monophosphate / Q000737:chemistry; D004553:Electric Conductivity; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D008745:Methylation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*
chemical_list: D009838:Oligodeoxyribonucleotides; D003843:Deoxycytidine Monophosphate; D006046:Gold; D003596:Cytosine; D004247:DNA