Electronic couplings in DNA pi-stacks: multistate effects

Alexander A Voityuk
Journal of Physical Chemistry. B 2005 September 29, 109 (38): 17917-21
In this study, we employ a multistate generalized Mulliken-Hush approach for calculating electronic couplings V(da) for charge transfer (CT) in DNA pi-stacks consisting of three, four, and five base pairs. In these systems the guanine donor and acceptor sites are separated by several (AT) pairs. The Hartree-Fock calculations of the stacks are carried out with the standard 6-31G basis sets. All possible superexchange pathways are accounted for. We examine electronic couplings estimated using the two-state and multistate models. Although for some systems the two-state scheme provides reasonable estimates of V(da), in general this simple model fails to reproduce the electronic couplings calculated with the multistate approach. The two-state treatment of pi-stacks with a tunneling gap less than 0.3 eV, for instance, GAAG and GAAAG, may lead to invalid estimates of V(da). We consider the dependence of V(da) on the length and composition of the bridge. The calculations show that V(da) is less sensitive to the arrangement of nucleobases in the bridge, as can be predicted on the basis of electronic couplings between adjacent base pairs.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"