InterPro domain: IPR022384

This entry represents the formiminotransferase (FT) domain of formiminotransferase-cyclodeaminase (FTCD), which forms a homodimer, with each protomer being comprised of two subdomains. Each subdomain has the structure consisting of an alpha/beta sandwich with antiparallel beta-sheet in the form (beta-alpha-beta)x2. Tetrahydrofolate (THF)-dependent glutamate formiminotransferase is involved in the histidine utilization pathway. This enzyme interconverts L-glutamate and N-formimino-L-glutamate. The enzyme is bifunctional as it also catalyzes the cyclodeaminase reaction on N-formimino-THF, converting it to 5,10-methenyl-THF and releasing ammonia; part of the process of regenerating THF. This model covers enzymes from metazoa as well as Gram-positive bacteria and archaea. In humans, deficiency of this enzyme results in a disease phenotype [ 1 ]. The crystal structure of the enzyme has been studied in the context of the catalytic mechanism [ 2 ].

This superfamily represents both individual subdomains of the formiminotransferase catalytic domain.

1. The molecular basis of glutamate formiminotransferase deficiency. Hum. Mutat. 22, 67-73
2. The crystal structure of the formiminotransferase domain of formiminotransferase-cyclodeaminase: implications for substrate channeling in a bifunctional enzyme. Structure 8, 35-46