Gas-phase interaction between DNA and RNA bases and copper(II) ion: A density functional study

This investigation, performed at Becke's three-parameter functional with Perdew-Wang correlational functional/6-311+G(2df,2p) level, can provide information about the geometry of all possible adducts originating from the interaction of Cu2+ cation with the most stable tautomers of DNA and RNA free bases. Several attachment sites for both purine and pyrimidine bases have been taken into account. Monocoordination or bicoordination has been observed in all the obtained complexes. The copper ion (II) has the major affinity for the most stable tautomer of guanine base. We have observed that an interesting behavior occurs when the copper ion interacts with the bases in an apical approach. (C) 2004 Wiley Periodicals, Inc.