The deamination of cytosine: an ab initio SCF mo study

Xu, Jie (1990) The deamination of cytosine: an ab initio SCF mo study. Masters thesis, Memorial University of Newfoundland.

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    Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
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Abstract

In 1974, Lindahl and Nyberg studied the rate of deamination of cytokine residues in single and double stranded DNA. After studying the rate at several temperatures the activation energy for the conversion of cytosine to uracil was estimated to be 121 kJ/mol. -- Possible mechanisms for deamination of cytosine are studied using ab initio SCF molecular orbital calculations. Ab initio calculations with STO-3G, 3-21G and 6-31G* basis sets have been performed to investigate the optimized structures and energies. -- First the deamination of amidine is studied as a model compound and the calculations are then extended to cytosine. The results for both calculations indicate that the rate-determining step (second step) with OH- has a barrier of 209 kJ/mol and with H₂O has a barrier of 174 kJ/mol. The results show that the reaction is hermodynamically favourable but kinetically not very favourable.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/4262
Item ID: 4262
Additional Information: Bibliography: leaves 157-161.
Department(s): Science, Faculty of > Chemistry
Date: 1990
Date Type: Submission
Library of Congress Subject Heading: Deamination; Cytosine; Molecular orbitals; Self-consistent field theory

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