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Introduction
acterofDNAunderambient conditions. ThedependenceofDNAconductanceon
the distance of the electrodeswas proposed by Tao et al.,[8] however in amacro-
scopic fashion. Stepwise decrease of conductancewas reported, as the individual
DNAmoleculesbetween theelectrodeswerebreaking.
The fundamental features of CT in DNA have been described as well. First, the
exponentialdependenceofCTefficiencyon the lengthof theDNAoligomers. Sec-
ond, the role of experimental setup that is both crucial and challenging to charac-
terize. In conclusion, carefully preparedDNAdevices exhibitedmeasurable con-
ductance, and this fact together with the practicable synthesis of even very long
DNAmoleculeswere the initial impulses for the contemplations on the potential
useofDNA-baseddevices innano-electronics.[14,15]
Albeit, thestructureof theDNAspecies in theseexperimentscouldnotberesolved
unambiguously. While it was concluded that the structure played a key role in
determining the conductance, it could only be guessed on the basis of observed
electricpropertieswhat the structural contourswere.
Allmentionedexperimental studies share thegeneral featuresof the experimental
setup.ADNAoligomerof several tensofbasepairs is linkedtometallic electrodes
viaathioalkylgroupattachedusuallytothe3’-endofeachoftheDNAstrands. The
distance of electrodes is or can be varied in the experiments, stretching theDNA
molecule, and theCTefficiency is affectedby the alteredDNAstructure. This fact
directs the focusof the intendedresearchtoaconsiderableextent to themechanical
properties of theDNAspeciesunder thegiven conditions. Thepotential ability of
DNA to stretch in biological processeswasmentioned already in 1953,[16] in an
article thatdirectly followedtheproposalofDNAstructurebyWatson&Crick.[17]
The responseofdsDNAstructure to stretching stresshasbeen studiedextensively
since the 1990s. First considerations on entropic elasticity of DNA [18] were fol-
lowedby studies on theDNA ‘overstretching’,[19, 20] and earlymodeling studies
revealed that dsDNAwoulddeformdifferently if the strands are pulled indiffer-
ent ways.[21, 22] Also, a structurewas proposed that DNAwould assume upon
stretching of the 3’-ends of each strand – so-called S-DNAwithmaintained inter-
strand base pairing but unwound, in a sort of a ladder structure. On the other
hand, when dsDNA was stretched and supercoiled, another new structure was
observed.[23]
6
Charge Transport in DNA
Insights from Simulations
- Title
- Charge Transport in DNA
- Subtitle
- Insights from Simulations
- Author
- Mario Wolter
- Publisher
- KIT Scientific Publishing
- Date
- 2013
- Language
- English
- License
- CC BY-SA 3.0
- ISBN
- 978-3-7315-0082-7
- Size
- 17.0 x 24.0 cm
- Pages
- 156
- Keywords
- Charge Transport, Charge Transfer, DNA, Molecular Dynamics, Quantum Mechanics
- Categories
- Naturwissenschaften Chemie
Table of contents
- Zusammenfassung 1
- Summary 3
- 1 Introduction 5
- 2 TheoreticalBackground 11
- 3 SimulationSetup 39
- 4 DNAUnderExperimentalConditions 49
- 5 ChargeTransport inStretchedDNA 69
- 6 ChargeTransport inMicrohydratedDNA 79
- 7 AParametrizedModel toSimulateCT inDNA 89
- 8 Conclusion 105
- Appendix 111
- A DNAUnderExperimentalConditions 111
- B CTinMicrohydratedDNA 117
- List ofPublications 137