2535-20-8Relevant articles and documents
Rapid preparation of isotopolog libraries by in vivo transformation of 13C-glucose. Studies on 6,7-dimethyl-8-ribitylluinazine, a biosynthetic precursor of vitamin B2
Illarionov, Boris,Fischer, Markus,Lee, Chan Yong,Bacher, Adelbert,Eisenreich, Wolfgang
, p. 5588 - 5594 (2004)
An Escherichia coli strain engineered for expression of the ribABGH genes of Bacillus subtilis was shown to produce 100 mg of the riboflavin precursor 6,7-dimethyl-8-ribityllumazine per liter of minimal medium. Growth of the recombinant strain in medium supplemented with [U-13C6] glucose and/or 15NH4Cl as single sources of carbon and/or nitrogen afforded 6,7-dimethyl-8-ribityllumazine universally labeled with 13C and/or 15N. The yield of [U-13C 13]-6,7-dimethyl-8-ribityllumazine based on [U-13C 6]glucose was 25 mg/g. Fermentation with [1-13C 1]-, [2-13C1]-, or [3-13C 1]glucose afforded mixtures of 6,7-dimethyl-8-ribityllumazine isotopologs, predominantly with 13C enrichment of single carbon atoms. The isotope-labeled samples enabled a comprehensive NMR analysis of 6,7-dimethyl-8-ribityllumazine. Isotopolog libraries of a wide variety of microbial metabolites can be produced by the same experimental approach.
Biosynthesis of riboflavin. Single turnover kinetic analysis of 6,7-dimethyl-8-ribityllumazine synthase
Schramek, Nicholas,Haase, Ilka,Fischer, Markus,Bacher, Adelbert
, p. 4460 - 4466 (2003)
6,7-Dimethyl-8-ribityllumazine synthase (lumazine synthase) catalyzes the condensation of 5-amino-6-ribitylamino-2,4-(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone 4-phosphate, affording the riboflavin precursor, 6,7-dimethyl-8-ribityllumazine. Single turnover experiments monitored by multiwavelength photometry were performed with the recombinant lumazine synthase of Bacillus subtilis. Mixing of the enzyme with the pyrimidine type substrate is conducive to a hypsochromic shift as well as a decrease in absorbance of the heterocyclic substrate; the rate constant for that reaction is 0.02 s-1 μM-1. Rapid mixing of the complex between enzyme and pyrimidine type substrate with the second substrate, 3,4-dihydroxy-2-butanone 4-phosphate, is followed by the appearance of an early optical transient characterized by an absorption maxima at 330 nm of low intensity which was tentatively assigned as a Schiff base intermediate. The subsequent elimination of phosphate affords a transient with intense absorption maxima at 455 and 282 nm, suggesting an intermediate with an extended system of conjugated double bonds. The subsequent formation of the enzyme product, 6,7-dimethyl-8-ribityllumazine, is the rate-determining step.
63. Isolierung und Struktur von Pteridinen (Lumazinen) aus Russula sp. (Taeublinge; Basidiomycetes)
Iten, Peter Xaver von,Maerki-Danzig, Hana,Koch, Herbert,Eugster, Conrad Hans
, p. 550 - 569 (1984)
Extensive chromatographic separations and chemical and spectroscopic investigations have led to the isolation and identification of several water-soluble pteridines from Russula sp., the so-called russupteridines, namely: 1-(5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl)amino-1-deoxy-D-ribitol (1; a pro-lumazine; first identification in a basidiomycete); 1-deoxy-1-(6-methyl-2,4,7-trioxo-1,2,3,4,7,8-hexahydropteridin-8-yl)-D-ribitol (3) and 1-deoxy-1-(2,4,7-trioxo-1,2,3,4,7,8-hexahydropteridin-8-yl)-D-ribitol (4); both compounds found for the first time in higher fungi; they belong to the components with the strongest violet-blue fluorescence in Russula sp.; riboflavine (6; now recognized as an important yellow colorant in a great many of Russula sp.); russupteridine-yellow 1 ( = 1-(6-amino-7-(N-formylimino)-2,4-dioxo-1,2,3,4,7,8-hexahydropteridin-8-yl)-1-deoxy-D-ribitol; 5; a component with very strong fluorescence; the first derivative of the novel 6,7-diamino-lumazine); russupteridine-yellow IV ( = 1-deoxy-1-(2,6,8-trioxo-2,4,5,6,7,8-hexahydro-1H-imidazolopteridin-4-yl)-D-ribitol (7).Two further yellow russupteridines (yellow II and yellow V) with very strong fluorescence have been isolated and characterized.
O-nucleoside, S-nucleoside, and N-nucleoside probes of lumazine synthase and riboflavin synthase
Talukdar, Arindam,Zhao, Yujie,Lv, Wei,Bacher, Adelbert,Illarionov, Boris,Fischer, Markus,Cushman, Mark
experimental part, p. 6239 - 6261 (2012/09/25)
Lumazine synthase catalyzes the penultimate step in the biosynthesis of riboflavin, while riboflavin synthase catalyzes the last step. O-Nucleoside, S-nucleoside, and N-nucleoside analogues of hypothetical lumazine biosynthetic intermediates have been synthesized in order to obtain structure and mechanism probes of these two enzymes, as well as inhibitors of potential value as antibiotics. Methods were devised for the selective cleavage of benzyl protecting groups in the presence of other easily reduced functionality by controlled hydrogenolysis over Lindlar catalyst. The deprotection reaction was performed in the presence of other reactive functionality including nitro groups, alkenes, and halogens. The target compounds were tested as inhibitors of lumazine synthase and riboflavin synthase obtained from a variety of microorganisms. In general, the S-nucleosides and N-nucleosides were more potent than the corresponding O-nucleosides as lumazine synthase and riboflavin synthase inhibitors, while the C-nucleosides were the least potent. A series of molecular dynamics simulations followed by free energy calculations using the Poisson-Boltzmann/surface area (MM-PBSA) method were carried out in order to rationalize the results of ligand binding to lumazine synthase, and the results provide insight into the dynamics of ligand binding as well as the molecular forces stabilizing the intermediates in the enzyme-catalyzed reaction.
A new series of N-[2,4-dioxo-6-D-ribitylamino-1,2,3,4-tetrahydropyrimidin- 5-yl]oxalamic acid derivatives as inhibitors of lumazine synthase and riboflavin synthase: Design, synthesis, biochemical evaluation, crystallography, and mechanistic implications
Zhang, Yanlei,Illarionov, Boris,Morgunova, Ekaterina,Jin, Guangyi,Bacher, Adelbert,Fischer, Markus,Ladenstein, Rudolf,Cushman, Mark
, p. 2715 - 2724 (2008/09/19)
(Figure Presented) The penultimate step in the biosynthesis of riboflavin is catalyzed by lumazine synthase. Three metabolically stable analogues of the hypothetical intermediate proposed to arise after phosphate elimination in the lumazine synthase-catalyzed reaction were synthesized and evaluated as lumazine synthase inhibitors. All three intermediate analogues were inhibitors of Mycobacterium tuberculosis lumazine synthase, Bacillus subtilis lumazine synthase, and Schizosaccharomyces pombe lumazine synthase, while one of them proved to be an extremely potent inhibitor of Escherichia coli riboflavin synthase with a Ki of 1.3 nM. The crystal structure of M. tuberculosis lumazine synthase in complex with one of the inhibitors provides a model of the conformation of the intermediate occurring immediately after phosphate elimination, supporting a mechanism in which phosphate elimination occurs before a conformational change of the Schiff base intermediate toward a cyclic structure.
