Comparison of the mechanism of deamination of 5,6-dihydro-5-methylcytosine with other cytosine derivatives

摘要

The mechanism of deamination of 5,6-dihydro-5-methylcytosine has been investigated theoretically and compared to those of other cytosine derivatives. The main goal is to understand the effect of C5-methylation and C5–C6 saturation upon the deamination rate. It is found that C5–C6 saturation tends to increase the local electrophilicity of the cytosine derivative on carbon C4. It is also concluded that C5-methylation displays an opposite effect on saturated versus unsaturated systems: on unsaturated systems, C5-methylation tends to increase the local electrophilicity on C4, while it reduces the local electrophilicity on C4 for saturated ones.