Homologous Superfamily

FMN-binding split barrel (IPR012349)

Short name: Split_barrel_FMN-bd

Overlapping entries


The FMN-binding domain has a split beta-barrel structure with a Greek-key topology that is related in structure to the ferredoxin reductase-like FAD-binding domain. The FMN-binding split barrel domain is found in pyridoxine 5'-phoshate oxidase (PNP oxidase), FMN-binding protein, ferric reductase, and in phenol 2-hydroxylase component B (PheA2).

PNP oxidase (EC: is an FMN flavoprotein that catalyses the oxidation of pyridoxamine-5-P (PMP) and pyridoxine-5-P (PNP) to pyridoxal-5-P (PLP). This reaction serves as the terminal step in the de novo biosynthesis of PLP in Escherichia coli, and as a part of the salvage pathway of this coenzyme in both E. coli and mammalian cells [PMID: 12686112, PMID: 12824491]. The binding sites for FMN and for substrate have been highly conserved throughout evolution.

The FMN-binding protein (FMN-bp) is one of the smallest proteins known to bind FMN. FMN-bp appears to participate in the electron-transfer pathway, and may have a structural relationship to the C-terminal domain of chymotrypsin [PMID: 9406543, PMID: 10713530].

Microbial ferric reductases are essential for generating more soluble ferrous iron to use in cellular proteins (assimilatory ferric reductases), and as terminal reductases of iron respiratory pathway of certain bacteria (dissimilatory iron reductases). Most assimilatory iron reductases are flavin enzymes [PMID: 12829278].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0048037 cofactor binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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