An anomalous dissociation of protonated cluster ions of DNA guanine-cytosine base-pair

Yeon-Mi Seong,Sang-Yun Han,Han-Bin Oh,Sung-Chan Jo

doi:10.5478/msl.2011.2.3.073

Abstract

In the collisionally-activated dissociation of the proton-bound cluster ions of DNA base guanine (G) and cytosine(C), G••H+••C, the abundance of [CH+] ions was found to be higher than that of [GH+] despite the fact that G has a higher protonaffinity than C. This unexpected observation seems to demonstrate another example that the simple kinetic method scheme doesnot work. We suggest that a kinetic factor or detailed dynamics governing the proton transfer and dissociation should be carefullyconsidered in the applications of the kinetic method to the proton affinity measurements.

Highlights

The kinetic method has been widely used for the thermochemical determination of gas-phase basicities, gas-phase acidities, proton affinities, electron affinities, ionization potentials, metal ion affinities, and so forrth.[1,2,3,4] In particular, the Cooks’ kinetic method is based on the measurements of relative rates of competitive dissociations of a cluster ion comprised of the compound of interest and a reference compound.[5]
We suggest that a kinetic factor or detailed dynamics governing the proton transfer and dissociation should be carefully considered in the applications of the kinetic method to the proton affinity measurements
We present another example of an anomalous dissociation of proton-bound complex of DNA guanine (G)-cytosine (C) base-pair

Summary

Introduction

The kinetic method has been widely used for the thermochemical determination of gas-phase basicities, gas-phase acidities, proton affinities, electron affinities, ionization potentials, metal ion affinities, and so forrth.[1,2,3,4] In particular, the Cooks’ kinetic method is based on the measurements of relative rates of competitive dissociations of a cluster ion comprised of the compound of interest and a reference compound.[5]. Abstract: In the collisionally-activated dissociation of the proton-bound cluster ions of DNA base guanine (G) and cytosine (C), GH+C, the abundance of [CH+] ions was found to be higher than that of [GH+] despite the fact that G has a higher proton affinity than C.

Results

Conclusion