GTP cyclohydrolase II (IPR032677)

Short name: GTP_cyclohydro_II

Overlapping homologous superfamilies

Domain relationships



This domain is found in members of the GTP cyclohydrolase II RibA-like superfamily. Members in this family includes GTP cyclohydrolase II, riboflavin biosynthesis protein RibBA and 3,4-dihydroxy-2-butanone 4-phosphate synthase.

GTP cyclohydrolase II is absent in higher eukaryotes, which makes it a potential antimicrobial drug target. The structure of GTP cyclohydrolase II reveals both a different protein fold to eukaryotic GTP cyclohydrolase I and distinctive molecular recognition determinants for GTP [PMID: 16115872].

GTP cyclohydrolase II (also known as ribA) catalyses the first committed step in the biosynthesis of riboflavin (vitamin b2). The enzyme converts GTP and water to formate, 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)- pyrimidine and pyrophosphate, and requires magnesium as a cofactor. In numerous bacteria and in plants, GTP cyclohydrolase II occurs in the C-terminal of a bifunctional enzyme known as ribBA, which also comprises an N-terminal 3,4-dihydroxy-2-butanone 4-phosphate synthase (DHBP_synthase, also known as RibB) (IPR000422). RibB catalyses the conversion of D-ribulose 5-phosphate to formate and 3,4-dihydroxy-2-butanone 4-phosphate [PMID: 10940330].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.