Photoelectrochemical evaluation of pH effect on hole transport through triplex-forming DNA immobilized on a gold electrode.
We characterized pH effect on hole transport through DNA duplexes possessing a partial triplex-forming region. Direct electrochemical measurement of the current response of photosensitizer-tethered DNA immobilized on a gold electrode revealed that the partial triplex formation under acidic conditions suppressed photocurrent due to hole transport, while dissociation of the triplex into the duplex as occurred upon increasing pH values recovered the photocurrent efficiency. Reversible conversion between duplex and triplex induced upon cyclic alternation of pH values resulted in a rise and fall of photocurrent responses, indicating that pH change may feature in the switching function of hole transport in DNA. These electrochemical behaviors could be correlated to the results obtained in long-range photo-oxidative DNA cleavage experiments, in which DNA cleavage at the hole trapping site beyond the triplex region was significantly suppressed under triplex-forming acidic conditions.
Haruna
Ken-ichi
K
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615-8510, Japan. hrn@pg.highway.ne.jp
Iida
Haruka
H
Tanabe
Kazuhito
K
Nishimoto
Sei-ichi
S
D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D010777:Photochemistry; D016062:Porosity
D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; C051802:triplex DNA; D006046:Gold; D004247:DNA