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We are deeply saddened by the passing of Amos Bairoch (1957–2025), the creator of PROSITE. We wish to dedicate our latest paper, published shortly before his death, to him. He will always be a source of inspiration to us.
Our deepest condolences go out to his family and friends, and to all those who had the privilege of working with him. Rest in peace, Amos. Your work will live on long after you are gone.
Amos Bairoch

PROSITE documentation PDOC00581
Riboflavin synthase alpha chain lumazine-binding repeat profile


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PURL: https://purl.expasy.org/prosite/documentation/PDOC00581

Description

Riboflavin synthase (RS-α) catalyzes the biosynthesis of riboflavin (vitamin B2) by dismutation of 6,7-dimethyl-8-(1'-D-ribityl)lumazine (Lum) (EC 2.5.1.9). Riboflavin synthases of bacteria and fungi are structurally and evolutionary related to antenna proteins involved in bioluminescence of marine bacteria [1,2]. These proteins seem to have evolved from the duplication of a domain of about 100 residues, the lumazine-binding repeat.

The 3D structure of RS-α, which is an asymmetric homotrimer, shows that both domains form a 6-stranded antiparallel β-barrel (see <PDB:1PKV>) [3], while a C-terminal helix is involved in trimerization. The Lum-binding domain of RS-α forms two Greek-key folds with the topology BBHBBBHB, where most of the substrate binding sites are located in β-strands (B) 4 and 5 and in helix (H) 2 [3,4,5].

Some proteins known to contain a lumazine-binding repeat:

  • Riboflavin synthase α chain (EC 2.5.1.9) (gene ribC in Escherichia coli, ribB in Bacillus subtilis and Photobacterium leiognathi, RIB5 in yeast). This enzyme synthesizes riboflavin from two molecules of Lum, a pteridine-derivative.
  • Photobacterium phosphoreum lumazine protein (LumP) (gene luxL). LumP is a protein that modulates the color of the bioluminescence emission of bacterial luciferase. In the presence of LumP, light emission is shifted to higher energy values (shorter wavelength). LumP binds non-covalently to 6,7-dimethyl-8-(1'-D-ribityl)lumazine.
  • Vibrio fischeri yellow fluorescent protein (YFP) (gene luxY). Like LumP, YFP modulates light emission but towards a longer wavelength. YFP binds non-covalently to FMN.

The profile we developed covers the entire lumazine-binding repeat.

Last update:

December 2005 / Pattern removed, profile added and text revised.

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Technical section

PROSITE method (with tools and information) covered by this documentation:

LUMAZINE_BIND, PS51177; Riboflavin synthase alpha chain lumazine-binding repeat profile  (MATRIX)


References

1AuthorsO'Kane D.J. Woodward B. Lee J. Prasher D.C.
TitleBorrowed proteins in bacterial bioluminescence.
SourceProc. Natl. Acad. Sci. U.S.A. 88:1100-1104(1991).
PubMed ID1996310

2AuthorsO'Kane D.J. Prasher D.C.
TitleEvolutionary origins of bacterial bioluminescence.
SourceMol. Microbiol. 6:443-449(1992).
PubMed ID1560772

3AuthorsMeining W. Eberhardt S. Bacher A. Ladenstein R.
TitleThe structure of the N-terminal domain of riboflavin synthase in complex with riboflavin at 2.6A resolution.
SourceJ. Mol. Biol. 331:1053-1063(2003).
PubMed ID12927541

4AuthorsTruffault V. Coles M. Diercks T. Abelmann K. Eberhardt S. Luttgen H. Bacher A. Kessler H.
TitleThe solution structure of the N-terminal domain of riboflavin synthase.
SourceJ. Mol. Biol. 309:949-960(2001).
PubMed ID11399071
DOI10.1006/jmbi.2001.4683

5AuthorsGerhardt S. Schott A.K. Kairies N. Cushman M. Illarionov B. Eisenreich W. Bacher A. Huber R. Steinbacher S. Fischer M.
TitleStudies on the reaction mechanism of riboflavin synthase: X-ray crystal structure of a complex with 6-carboxyethyl-7-oxo-8-ribityllumazine.
SourceStructure 10:1371-1381(2002).
PubMed ID12377123



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