InterPro domain: IPR043134

GTP cyclohydrolase I ( 3.5.4.16 ) catalyses the biosynthesis of formic acid and dihydroneopterin triphosphate from GTP [ 1 ]. This reaction is the first step in the biosynthesis of tetrahydrofolate in prokaryotes, of tetrahydrobiopterin in vertebrates, and of pteridine-containing pigments in insects. The comparison of the sequence of the enzyme from bacterial and eukaryotic sources shows that the structure of this enzyme has been extremely well conserved throughout evolution [ 2 ].

This superfamily entry consists of the N-terminal domain found in GTP cyclohydrolases I (GTP-CH-I), which has been well conserved throughout evolution across bacterial and eukaryotic species. The GTP-CH-I monomer folds into an alpha beta structure with a predominantly helical N-terminal part [ 3 ].

1. Biosynthesis of pteridines. Reaction mechanism of GTP cyclohydrolase I. J. Mol. Biol. 326, 503-16
2. Homology cloning of GTP-cyclohydrolase I from various unrelated eukaryotes by reverse-transcription polymerase chain reaction using a general set of degenerate primers. Biochem. Biophys. Res. Commun. 212, 705-11
3. Atomic structure of GTP cyclohydrolase I. Structure 3, 459-66