TY - JOUR
T1 - Thio- versus oxo-derivatives of DNA bases
T2 - Theoretical study on possible mutagenic effect of sulfur atom
AU - Furmanchuk, Al'ona
AU - Leszczynski, Jerzy
N1 - Funding Information:
This work was supported by the NSF CREST Grant (HRD-0318519). We thank the Mississippi Center for Supercomputing Research (MCSR) for a generous allotment of computer time.
PY - 2008/6
Y1 - 2008/6
N2 - The molecular structures, energetics and mechanisms of proton transfer in 9-methyl-2N-substituted guanines and thioguanines have been studied at the gas phase (QCISD/cc-pVDZ//B3lyp/6-31G(d,p)) and polar solvent (IEFPCM//B3LYP/6- 31G(d,p)) environments. Calculations predict the height of the proton transfer barrier for the thione → thiol reactions to be approximately 2-3 times lower than that for the keto → enol process. Similarly, presence of sufficiently long 2N substituent with the terminal OH group reduces the barrier. The polar media (water) significantly stabilizes thione and keto forms. Tautomeric concentration ratio and rate constants have also been calculated for all the considered processes.
AB - The molecular structures, energetics and mechanisms of proton transfer in 9-methyl-2N-substituted guanines and thioguanines have been studied at the gas phase (QCISD/cc-pVDZ//B3lyp/6-31G(d,p)) and polar solvent (IEFPCM//B3LYP/6- 31G(d,p)) environments. Calculations predict the height of the proton transfer barrier for the thione → thiol reactions to be approximately 2-3 times lower than that for the keto → enol process. Similarly, presence of sufficiently long 2N substituent with the terminal OH group reduces the barrier. The polar media (water) significantly stabilizes thione and keto forms. Tautomeric concentration ratio and rate constants have also been calculated for all the considered processes.
KW - 9-methyl-2N-substituted guanines
KW - 9-methyl-2N-substituted thioguanines
KW - Ab initio
KW - Tautomeric equilibrium
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U2 - 10.1080/17415990802195607
DO - 10.1080/17415990802195607
M3 - Article
AN - SCOPUS:45849091164
SN - 1741-5993
VL - 29
SP - 401
EP - 413
JO - Journal of Sulfur Chemistry
JF - Journal of Sulfur Chemistry
IS - 3-4
ER -