Protein Family Models

This family includes the beta chain of 6,7-dimethyl-8- ribityllumazine synthase EC:2.5.1.9, an enzyme involved in riboflavin biosynthesis. The family also includes a subfamily of distant archaebacterial proteins that may also have the same function for example Swiss:O28856. The family contains a number of different subsets including a family of proteins comprising archaeal lumazine and riboflavin synthases, type I lumazine synthases, and the eubacterial type II lumazine synthases [1]. It has been established that lumazine synthase catalyses the penultimate step in the biosynthesis of riboflavin in plants and microorganisms. The type I lumazine synthases area active in pentameric or icosahedral quaternary assemblies, whereas the type II are decameric [2]. Brucella, a bacterial genus that causes brucellosis, and other Rhizobiales have an atypical riboflavin metabolic pathway. Brucella spp code for both a type-I and a type-II lumazine synthase, and it has been shown that at least one of these two has to be present in order for Brucella to be viable, showing that in the case of Brucella flavin metabolism is implicated in bacterial virulence [3]. [1]. 16923880. Evolution of vitamin B2 biosynthesis: 6,7-dimethyl-8-ribityllumazine synthases of Brucella. Zylberman V, Klinke S, Haase I, Bacher A, Fischer M, Goldbaum FA;. J Bacteriol. 2006;188:6135-6142. [2]. 17854827. Structural and kinetic properties of lumazine synthase isoenzymes in the order Rhizobiales. Klinke S, Zylberman V, Bonomi HR, Haase I, Guimaraes BG, Braden BC, Bacher A, Fischer M, Goldbaum FA;. J Mol Biol. 2007;373:664-680. [3]. 20195542. An atypical riboflavin pat. TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-10-16

6,7-dimethyl-8-ribityllumazine synthase catalyzes the formation of 6,7-dimethyl-8-ribityllumazine by condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone in riboflavin biosynthesis pathway

Date:

2023-02-28

Gene:

ribE

Date:

2021-08-12

This enzyme catalyzes the cyclo-ligation of 3,4-dihydroxy-2-butanone-4-P and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione to form 6,7-dimethyl-8-ribityllumazine, the immediate precursor of riboflavin. Sometimes referred to as riboflavin synthase, beta subunit, this should not be confused with the alpha subunit which carries out the subsequent reaction. Archaeal members of this family are considered putative, although included in the seed and scoring above the trusted cutoff.

Gene:

ribH

Date:

2021-05-06