Entry M0031 184.108.40.206 thymidylate synthase
The negatively charged nitrogen of dihydrofolate eliminates a hydride ion, which adds to the CH2=C group of the covalently attached methyl-dUMP, causing the elimination of Cys198.
Comment: There are two alternative mechanisms proposed for this hydride transfer step. The first is a single step transfer in which the Trp82 stabilises a positively charged trsnaition state. The second is that the hydride transfer may occur by two single-electron transfers with Trp82 stabilising the radical cation intermediate through long-range electrostatic effects. The precise positioning of H-C6 over the site of htydride transfer suggests that the singe step (shown here) is likely .
Amino acids involved in the reaction step.
||Bonds Changed in Order
||Atom Types Involved
The C-C bond changes from a single to double bond
The C-N bond changes from a single to double bond
The C-C bond changes from a double to single bond
View similar reactions in MACiE.