The catalytic mechanism of one-carbon unit transfer between AICA and N10-formyl-tetrahydrofolate: an ONIOM study

The catalytic mechanism of one-carbon unit transfer between 5-amino-4-carboxamide imidazole (AICA) and N10-formyl-tetrahydrofolate (10f-H4F) is investigated by ONIOM approach. There are two different channels for proton transfer in this reaction, resulting in two reaction pathways with different properties. Our results indicate that proton transfer process is the rate-limiting step, and the intermolecular H-bond contributes much to the activation energy. Furthermore, the influence of the substituent linked to C4 atom of AICA is also discussed. The results from our calculations are consistent with experiment very well.