InterPro domain: IPR020602

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 entry represents a common fold found in GTP cyclohydrolase I [ 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. From cyclohydrolase to oxidoreductase: discovery of nitrile reductase activity in a common fold. Proc. Natl. Acad. Sci. U.S.A. 102, 4264-9