The structures of [CuII+base] complex have been studied extensively over several decades because of the significance of Copper(Ⅱ) ion in biological processes. It is evident that several reports are not consistent with each other and that no clear ag...
The structures of [CuII+base] complex have been studied extensively over several decades because of the significance of Copper(Ⅱ) ion in biological processes. It is evident that several reports are not consistent with each other and that no clear agreement exists regarding the biological active structure of [CuII+base] complex during the biological process. We focus on the binding sites between the CuII ion and the [Cytosine+Guanine] molecule to explain the biological effect in terms of a gas-phase structural difference. We present the results of the Ion-trap Electrospray Ionization(ESI) mass spectrometry(MS) and MS/MS study regarding the interaction of metal ions with the [Cytosine+Guanine] molecule. Ab initio calculations are also performed with 6-31G* basis sets to determine optimized structures and energies. Density functional theory (DFT) at the B3LYP level is carried out using the Gaussian03 series program. Three group ([CuII+C(O2, N3)G(O6, N7)-H]+1, [CuII+C(N3, N4)G(O6, N7)-H]+1, [CuII+CG(O6, N7)-H]+1) of complex structures are optimized. And energies of complexes are calculated to decide the possible geometry of complex structure. [CuII+C(O2, N3)G(O6, N7)-H]+1 complex is suggested as the most stable structure among [CuII+CG-H]+1 complexes.