Domain

Lumazine-binding domain (IPR026017)

Short name: Lumazine-bd_dom

Domain relationships

None.

Description

The lumazine-binding domain is about 100 residues. In its C-terminal section, this domain contains a conserved motif [KR]-V-N-[LI]-E which has been proposed to be the binding site for lumazine (Lum) and some of its derivatives. Riboflavin synthase alpha chain (RS-alpha), which binds two molecules of Lum, has two perfect copies of this motif, while lumazine protein (LumP), which binds one molecule of Lum, has a Glu instead of Lys/Arg in the first position of the second copy of the motif. Similarly, yellow fluorescent protein (YFP), which binds to one molecule of FMN, also seems to have a potentially dysfunctional binding site by substitution of Gly for Glu in the last position of the first copy of the motif.

The lumazine-binding domain of RS-alpha forms two Greek-key folds with the topology BBHBBBHB, where most of the substrate binding sites are located in beta-strands (B) 4 and 5 and in helix (H) 2 [PMID: 12927541, PMID: 11399071, PMID: 12377123].

Contributing signatures

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