ChemInform Abstract: 19F NMR Ligand Perturbation Studies on 6,7-Bis(trifluoromethyl)-8-ribityllumazine-7-hydrates and the Lumazine Synthase Complex of Bacillus subtilis. Site-Directed Mutagenesis Changes the Mechanism and the Stereoselectivity of the Cata

Autor: Karl Kugelbrey, Mark Cushman, Markus Fischer, Adelbert Bacher, Sevil Weinkauf, Johannes Scheuring
Rok vydání: 2010
Předmět:
Zdroj: ChemInform. 32
ISSN: 1522-2667
0931-7597
DOI: 10.1002/chin.200137218
Popis: The riboflavin synthase/lumazine synthase complex of Bacillus subtilis catalyzes the last two steps in riboflavin biosynthesis. The protein comprises a capsid of 60 β subunits with lumazine synthase activity and a core of three α subunits with riboflavin synthase activity. The β subunits catalyze the formation of 6,7-dimethyl-8-ribityllumazine (3) from 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione (1) and 3,4-dihydroxy-2-butanone 4-phosphate (2). Complexes of recombinant lumazine synthase (β60 capsids) with 6-trifluoromethyl-7-oxo-8-ribityllumazine (10) as well as 7S- or 7R-6,7-bistrifluoromethyl-8-ribityllumazine hydrate (11) were studied by 19F NMR spectroscopy. Despite the large molecular weight of approximately 960 kDa of the protein, spectra with separated signals of free and bound ligand could be obtained. An unusually large shift difference of 8 ppm was observed between the 7-trifluoromethyl signals of free and bound ligand for epimer B of 11 and the enzyme. The signal is sensitive to the repla...
Databáze: OpenAIRE
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