DNA electrochemistry as a probe of base pair stacking in A-, B-, and Z-form DNA.
DNA-mediated charge transport (CT) chemistry is sensitive to DNA structure and base pair stacking. In an electrochemical assay based upon DNA CT, DNA-modified electrode surfaces are used to examine the electrochemical reduction of methylene blue (MB), a small molecule that binds to the DNA film by intercalation. Here electrochemically we probe CT in the three primary conformations of double-stranded nucleic acids, A-, B-, and Z-form DNA. The A-form is examined in the context of a DNA/RNA hybrid duplex and Z-DNA, in duplexes containing d((m)CG)(8) sequences at high Mg(2+) concentrations. We find that both A- and B-DNA support efficient DNA CT as measured by MB reduction in the DNA film; a lower level of reduction is evident with the Z-form film. Furthermore, mismatches incorporated into A-form duplexes, as in B-form duplexes, disrupt MB reduction, thus providing a strategy for mutation detection through testing of RNA transcripts at DNA electrodes.
Boon
Elizabeth M
EM
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Barton
Jacqueline K
JK
D020137:Base Pair Mismatch; D020029:Base Pairing; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D017403:In Situ Hybridization; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry; D010084:Oxidation-Reduction; D012313:RNA / Q000737:chemistry
D009841:Oligonucleotides; D012313:RNA; D004247:DNA