The formiminotransferase (FT) domain of formiminotransferase-cyclodeaminase (FTCD) forms a homodimer, with each protomer comprising two subdomains. The formiminotransferase domain has an N-terminal subdomain that is made up of a six-stranded mixed beta-pleated sheet and five alpha helices, which are arranged on the external surface of the beta sheet. This, in turn, faces the beta-sheet of the C-terminal subdomain to form a double beta-sheet layer. The two subdomains are separated by a short linker sequence, which is not thought to be any more flexible than the remainder of the molecule. The substrate is predicted to form a number of contacts with residues found in both the N-terminal and C-terminal subdomains.[2] In humans, deficiency of this enzyme results in a diseasephenotype.[3]
^Kohls D, Sulea T, Purisima EO, MacKenzie RE, Vrielink A (January 2000). "The crystal structure of the formiminotransferase domain of formiminotransferase-cyclodeaminase: implications for substrate channeling in a bifunctional enzyme". Structure. 8 (1): 35–46. doi:10.1016/S0969-2126(00)00078-2. PMID10673422.
^Hilton JF, Christensen KE, Watkins D, Raby BA, Renaud Y, de la Luna S, Estivill X, MacKenzie RE, Hudson TJ, Rosenblatt DS (July 2003). "The molecular basis of glutamate formiminotransferase deficiency". Hum. Mutat. 22 (1): 67–73. doi:10.1002/humu.10236. PMID12815595.