Title

Product ion studies of diastereomeric benzo[ghi]fluoranthene-2′- deoxynucleoside adducts by electrospray ionization and quadrupole ion trap mass spectrometry

Document Type

Conference Proceeding

Date of Original Version

1-31-2006

Abstract

The product ion formation characteristics of the protonated molecule ions generated from 10 different deoxynucleoside adducts of benzo[ghi]fluoranthene (B[ghi]F) have been studied using electrospray ionization (ESI) and quadrupole ion trap mass spectrometry to gain a better understanding of the fragmentation mechanisms that govern structure-specific fragmentation. The reaction of the syn- and anti-diastereomers of trans-3,4-dihydroxy-5,5a-tetrahydrobenzo[ghi] fluoranthene with DNA produce four deoxyguanosine, four deoxyadenosine, and two deoxycytidine adducts whose structures differ based on the cis/trans arrangement of the hydroxyl groups and nucleic acids bound to B[ghi]F. Those adducts that have structures where the nucleic acid and 3′-hydroxyl group of B[ghi]F are cis with respect to each other undergo extensive water loss whereas those isomers where the nucleic acid and 3′-hydroxyl group are trans do not. These results are consistent with a mechanism of water loss initiated by a hydrogen-bonding interaction between the charge-bearing proton on a heterocyclic nitrogen atom on the nucleic acid and the 3′-hydroxyl oxygen on the PAH. The dG and dC adducts are observed to undergo more extensive water loss than the dA adducts. Molecular modeling indicates that the larger relative abundances of the product ions formed by water loss for the dG and dC relative to dA are due to stronger hydrogen-bonding interactions prior to fragmentation and the greater stability of the carbocations formed at the C3′ carbon after fragmentation. © 2005 Elsevier B.V. All rights reserved.

Publication Title

Analytica Chimica Acta

Volume

557

Issue

1-2

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