| 6,7-dimethyl-8-ribityllumazine synthase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 2.5.1.78 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| |||||||||
Lumazine synthase (EC 2.5.1.78, 6,7-dimethyl-8-ribityllumazine synthase, 6,7-dimethyl-8-ribityllumazine synthase 2, 6,7-dimethyl-8-ribityllumazine synthase 1, lumazine synthase 2, lumazine synthase 1, type I lumazine synthase, type II lumazine synthase, RIB4, MJ0303, RibH, Pbls, MbtLS, RibH1 protein, RibH2 protein, RibH1, RibH2) is an enzyme with systematic name 5-amino-6-(D-ribitylamino)uracil butanedionetransferase. [1] This enzyme catalyses the following chemical reaction
- 1-deoxy-L-glycero-tetrulose 4-phosphate + 5-amino-6-(D-ribitylamino)uracil 6,7-dimethyl-8-(D-ribityl)lumazine + 2 H2O + phosphate
-
This reaction is part of the biosynthesis of riboflavin (vitamin B2). Lumazine synthase is thus found in those organisms (plants, fungi and most microorganisms) which produce riboflavin. [2]
Depending on the species, 5, 10 or 60 copies of the enzyme bind together to form homomers. In the case of 60 copies, the enzyme units form a icosahedral hollow cage. In some bacteria, this cage contains another enzyme involved in the riboflavin synthesis, riboflavin synthase. [2]
These icosahedral cages have been investigated for use in drug delivery or as vaccines, delivering antigens. [2] Using directed evolution, Lumazine synthase has been modified so that it forms larger cages that preferentially package RNA molecules that code for the protein, akin to a virus capsid. [3]
