Role of Adenine and Guanine Sites in Hole Hopping in DNA Nanowire

Kaur, Inderpreet and Kulkarni, G.S. and Ajore, Ram and Bharadwaj, Richa and Singh, Nirmal and Bharadwaj, L.M. (2009) Role of Adenine and Guanine Sites in Hole Hopping in DNA Nanowire. Journal of Theoretical and Computational Chemistry, 8 (3). pp. 529-539. ISSN 0219-6336

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Transfer integrals for oligos with different bases have been calculated using INDO/Koopman's approximation to unveil the charge transport mechanism in DNA. The sequences, G(A)nG, n = 1, 2, …, 10; G(A)xG(A)yG, x + y = 9; and G(A)xG(A)y G(A)zG, x + y + z = 8, were employed to interpret the Guanine (G) and Adenine(A) hopping. Adenine hopping is found to be faster in G(A)nG sequences with longer Adenine bridges (n ≥ 3). Inserting G-bases in between G(A)10G led to a decrease in the value of transfer integrals. Close analysis has revealed that bridge closer to 3′-end forms a hopping bottleneck; however, the presence of bridge at 5′-end enhances the charge transfer through A-hopping. Further insertion of single G sites in G(A)xG(A)yG (where x + y = 9) reduces the transfer integrals, thus explaining the hampering of A-hopping. Hence, sequences of the type G(A)nG, n > 3, are better suited for their application as molecular wire. Finally, studies on the effect of flipping of bases, i.e. flipping G:C to C:G on transfer integrals, have revealed that helical distortions and conformational changes due to sequence variations lead to changes in coupling, which is highly unpredictable.

Item Type: Article
Uncontrolled Keywords: DNA nanowire; coupling parameters; molecular electronics; HOMO–LUMO; population analysis
Subjects: CSIO > Nano Science and Nano Technology
Depositing User: Ms. J Shrivastav
Date Deposited: 30 Mar 2012 11:17
Last Modified: 30 Mar 2012 11:17

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