title: Tetrakis-acridinyl peptide: distance dependence of photoinduced electron transfer in deoxyribonucleic acid assemblies.
abstract: The distance dependence of photoinduced electron transfer in deoxyribonucleic acid (DNA) duplex was investigated using the "TAP cassette" systems of the general formula (AT)6A(n)XA(9-n) (X denote guanine (G) or cytosine (C)). The tetrakis-9-acridinyl peptide (TAP) binds tightly with (AT)6 duplex region showing strong fluorescence that was not quenched by the A(n)XA(9-n) single-stranded region. Quenching was observed after duplex formation with the complementary T(9-n)XT(n) strand (G-C pairing), showing clear dependence on the distance between the TAP and a guanine. An extremely low beta value of 0.22 was obtained in our electron transfer (ET) system that suggests exceptional good mediation of ET process. Experiments with G-mismatches showed negligible quenching for systems with guanine separated by more than one AT base pair that indicated rather inefficient ET process for duplexes containing disrupted pi-electronic system.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Mizuki
authors.forename: Takahiko
authors.initials: T
authors.lastname: Nojima
authors.forename: Bernard
authors.initials: B
authors.lastname: Juskowiak
authors.forename: Shigeori
authors.initials: S
authors.lastname: Takenaka