title: Random isotopolog libraries for protein perturbation studies. 13C NMR studies on lumazine protein of Photobacterium leiognathi.
abstract: [graph: see text] Lumazine proteins of luminescent bacteria are paralogs of riboflavin synthase which are devoid of catalytic activity but bind the riboflavin synthase substrate, 6,7-dimethyl-8-ribityllumazine, with high affinity and are believed to serve as optical transponders for bioluminescence emission. Lumazine protein of Photobacterium leiognathi was expressed in a recombinant Escherichia coli host and was reconstituted with mixtures (random libraries) of 13C-labeled isotopologs of 6,7-dimethyl-8-ribityllumazine or riboflavin that had been prepared by biotransformation of [U-(13)C6]-, [1-(13)C1]-, [2-(13)C1]-, and [3-(13)C1]glucose. 13C NMR analysis of the protein/ligand complexes afforded the assignments of the 13C NMR chemical shifts for all carbon atoms of the protein-bound ligands by isotopolog abundance editing. The carbon atoms of the ribityl groups of both ligands studied were shifted up to 6 ppm upon binding to the protein. Chemical shift modulation of the side chain and chromophore carbon atoms due to protein/ligand interaction is discussed on the basis of the sequence similarity between lumazine protein and riboflavin synthase.
authors.affiliation: Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Illarionov
authors.forename: Chan Yong
authors.initials: CY
authors.lastname: Lee
authors.forename: Adelbert
authors.initials: A
authors.lastname: Bacher
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry*; D002247:Carbon Isotopes; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering; D005947:Glucose / Q000737:chemistry; D008024:Ligands; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010776:Photobacterium / Q000737:chemistry*; D011621:Pteridines / Q000737:chemistry; D012015:Reference Standards; D012256:Riboflavin / Q000737:chemistry; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D008024:Ligands; D008164:Luminescent Proteins; D011621:Pteridines; C026648:lumazine protein, Photobacterium; C001061:6,7-dimethyl-8-ribityllumazine; D005947:Glucose; D012256:Riboflavin