GTP cyclohydrolase I, feedback regulatory protein (IPR009112)

Short name: GTP_CycHdrlase_I_reg

Overlapping homologous superfamilies

Family relationships



GTP cyclohydrolase I feedback regulatory protein (GFRP) in mammals helps regulate the biosynthesis of tetrahydrobiopterin through the feedback inhibition of the rate-limiting enzyme GTP cyclohydrolase I (GTPCHI). Tetrahydrobiopterin is the cofactor required for the hydroxylation of aromatic amino acids. The crystal structure of GFRP reveals that the protein forms a homopentamer [PMID: 11580249]. In the presence of phenylalanine, the stimulatory complex consists of a GTPCHI decamer sandwiched by two GFRP pentamers, which is thought to enhance GTPCHI activity by locking the enzyme in the active state [PMID: 11818540]. The structure of GFRP consists of two alpha/beta layers arranged beta(2)-alpha-beta(2)-alpha-beta(2), with antiparallel beta-sheets in the order 342165.

GO terms

Biological Process

GO:0009890 negative regulation of biosynthetic process

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

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