The Kinetics of Charge Recombination in DNA Hairpins Controlled by Counterions

Abstract

Abstract. The charge recombination rate in DNA hairpins is investigated. The distance dependence for the charge recombination rate between stilbene donor (Sd + ) and stilbene acceptor (Sa − ) linkers separated by an AT bridge has a double exponential form. We suggest that this dependence is associated with two tunneling channels distinguished by the presence or absence of the Cl − counterion bound to Sd + . Experimentbased estimates of counterion binding parameters agree within reasonable expectations. A control experiment replacing the Cl − ion with other halide ions is suggested. Counterion substitution allows modification of the charge recombination rate in either direction by orders of magnitude.