title: Impact of single basepair mismatches on electron-transfer processes at Fc-PNA⋅DNA modified gold surfaces.
abstract: Gold-surface grafted peptide nucleic acid (PNA) strands, which carry a redox-active ferrocene tag, present unique tools to electrochemically investigate their mechanical bending elasticity based on the kinetics of electron-transfer (ET) processes. A comparative study of the mechanical bending properties and the thermodynamic stability of a series of 12-mer Fc-PNA⋅DNA duplexes was carried out. A single basepair mismatch was integrated at all possible strand positions to provide nanoscopic insights into the physicochemical changes provoked by the presence of a single basepair mismatch with regard to its position within the strand. The ET processes at single mismatch Fc-PNA⋅DNA modified surfaces were found to proceed with increasing diffusion limitation and decreasing standard ET rate constants k(0)  when the single basepair mismatch was dislocated along the strand towards its free-dangling Fc-modified end. The observed ET characteristics are considered to be due to a punctual increase in the strand elasticity at the mismatch position. The kinetic mismatch discrimination with respect to the fully-complementary duplex presents a basis for an electrochemical DNA sensing strategy based on the Fc-PNA⋅DNA bending dynamics for loosely packed monolayers. In a general sense, the strand elasticity presents a further physicochemical property which is affected by a single basepair mismatch which may possibly be used as a basis for future DNA sensing concepts for the specific detection of single basepair mismatches.
authors.affiliation: Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Hüsken
authors.forename: Magdalena
authors.initials: M
authors.lastname: Gębala
authors.forename: Alberto
authors.initials: A
authors.lastname: Battistel
authors.forename: Fabio
authors.initials: F
authors.lastname: La Mantia
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuhmann
authors.forename: Nils
authors.initials: N
authors.lastname: Metzler-Nolte
mesh_terms: D020137:Base Pair Mismatch; D001483:Base Sequence; D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004579:Electron Transport; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D020135:Peptide Nucleic Acids / Q000737:chemistry*; D044367:Phase Transition; D013499:Surface Properties
chemical_list: D020135:Peptide Nucleic Acids; D006046:Gold; D004247:DNA