This superfamily represents the duplication domain in 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferases (AICARFTs, also AICAR transformylase or AICAR Tfase). It has a three layer alpha-beta-alpha sandwich structure.

AICARFT can be part of a bifunctional enzyme (ATIC, the gene product of purH) catalysing the last two steps in de novo purine biosynthesis. ATIC also has an IMP (inosine monophosphate) cyclohydrolase (IMPCHase) functional domain. The bifunctional enzyme forms an intertwined dimer where each monomer is composed of two separate functional domains. AICARFT catalyses the formylation of 5-aminoimidazole-4-carboxamide-ribonucleotide (AICAR) by N-10-formyl-tetrahydrofolate (10-formyl-THF) to produce formyl-AICAR (FAICAR) and THF. ATIC is an attractive candidate for the design of anti-cancer agents, since cancer cells rely more heavily on the de novo purine biosynthesis pathway than normal cells.

PFAM:PF01808, INTERPRO:IPR024051,PMID:11323713,PMID:12501179,PMID:15355974