Sequence-Specific Electron Transfer Mediated by DNA Duplexes Attached to Gold through the Alkanethiol Linkern

TY - JOUR

T1 - Sequence-Specific Electron Transfer Mediated by DNA Duplexes Attached to Gold through the Alkanethiol Linkern

AU - Kekedy-Nagy, Laszlo

AU - Ferapontova, Elena E.

PY - 2018/11/8

Y1 - 2018/11/8

N2 - Ability of the DNA double helix to transport electrons is its critical feature, underlying a number of important biological and biotechnological processes. Here, we show that electron transfer (ET) from the gold electrode to the DNA-bound methylene blue (MB) mediated by the DNA base-pair π-stack is less efficient in (dGdC)-rich duplexes compared to pure (dAdT) DNA. The ET rate constant k s extrapolated to the DNA surface coverage Δ DNA → 0 is 121 ± 8 s -1 for (dAdT) 25, being almost twofold higher than 67 ± 3 s -1 shown for (dGdC) 20, consistent with the electric-field-disturbed submolecular structure of the (dGdC) 20 duplex earlier shown at electrified interfaces. DNA-mediated ET occurs both to MB intercalated and thus perfectly π-stacked into the (dGdC) 20 duplex and to MB solely groove-bound to (dAdT) 25. For both (dGdC) 20 and (dAdT) 25, ET is less efficient than ET in DNA duplexes of a mixed dA, dT, dG, dC composition. The results suggest new interpretations of the biological ET processes that may occur in dsDNA of different compositions at polarized interfaces.

AB - Ability of the DNA double helix to transport electrons is its critical feature, underlying a number of important biological and biotechnological processes. Here, we show that electron transfer (ET) from the gold electrode to the DNA-bound methylene blue (MB) mediated by the DNA base-pair π-stack is less efficient in (dGdC)-rich duplexes compared to pure (dAdT) DNA. The ET rate constant k s extrapolated to the DNA surface coverage Δ DNA → 0 is 121 ± 8 s -1 for (dAdT) 25, being almost twofold higher than 67 ± 3 s -1 shown for (dGdC) 20, consistent with the electric-field-disturbed submolecular structure of the (dGdC) 20 duplex earlier shown at electrified interfaces. DNA-mediated ET occurs both to MB intercalated and thus perfectly π-stacked into the (dGdC) 20 duplex and to MB solely groove-bound to (dAdT) 25. For both (dGdC) 20 and (dAdT) 25, ET is less efficient than ET in DNA duplexes of a mixed dA, dT, dG, dC composition. The results suggest new interpretations of the biological ET processes that may occur in dsDNA of different compositions at polarized interfaces.

KW - METHYLENE-BLUE

KW - CHARGE-TRANSPORT

KW - NUCLEIC-ACIDS

KW - ELECTROCHEMISTRY

KW - MOLECULES

KW - SURFACE

KW - FILMS

KW - REDOX

KW - END

KW - ELECTROANALYSIS

UR - http://www.scopus.com/inward/record.url?scp=85056166513&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcb.8b07505

DO - 10.1021/acs.jpcb.8b07505

M3 - Journal article

C2 - 30336034

SN - 1520-6106

VL - 122

SP - 10077

EP - 10085

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

IS - 44

ER -