Homologous Superfamily

Inosine monophosphate cyclohydrolase-like superfamily (IPR036795)

Short name: IMP_cyclohydrolase-like_sf

Overlapping entries


This entry represents inosine monophosphate (IMP) cyclohydrolase superfamily, found in archaeal species, as well as some bacterial proteins of unknown function.

IMP cyclohydrolase catalyses the cyclisation of 5-formylamidoimidazole-4-carboxamide ribonucleotide to IMP, a reaction which is important in de novo purine biosynthesis in archaeal species [PMID: 11844782]. This single domain protein is arranged to form an overall fold that consists of a four-layered alpha-beta-beta-alpha core structure. The two antiparallel beta-sheets pack against each other and are covered by alpha-helices on one face of the molecule. The protein is structurally similar to members of the N-terminal nucleophile (NTN) hydrolase superfamily. A deep pocket was in fact found on the surface of IMP cyclohydrolase in a position equivalent to that of active sites of NTN-hydrolases, but an N-terminal nucleophile could not be found. Therefore, it is thought that this enzyme is structurally but not functionally similar to members of the NTN-hydrolase family [PMID: 12012346].

In bacteria this step is catalysed by a bifunctional enzyme (purH).

GO terms

Biological Process

GO:0006188 IMP biosynthetic process
GO:0006164 purine nucleotide biosynthetic process

Molecular Function

GO:0003937 IMP cyclohydrolase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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