title: Structure of lumazine protein, an optical transponder of luminescent bacteria.
abstract: The intensely fluorescent lumazine protein is believed to be involved in the bioluminescence of certain marine bacteria. The sequence of the catalytically inactive protein resembles that of the enzyme riboflavin synthase. Its non-covalently bound fluorophore, 6,7-dimethyl-8-ribityllumazine, is the substrate of this enzyme and also the committed precursor of vitamin B(2). An extensive crystallization screen was performed using numerous single-site mutants of the lumazine protein from Photobacterium leiognathi in complex with its fluorophore and with riboflavin, respectively. Only the L49N mutant in complex with riboflavin yielded suitable crystals, allowing X-ray structure determination to a resolution of 2.5 A. The monomeric protein folds into two closely similar domains that are structurally related by pseudo-C(2) symmetry, whereby the entire domain topology resembles that of riboflavin synthase. Riboflavin is bound to a shallow cavity in the N-terminal domain of lumazine protein, whereas the C-terminal domain lacks a ligand.
authors.affiliation: Lehrstuhl für Biologische Chemie, Technische Universität München, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Chatwell
authors.forename: Victoria
authors.initials: V
authors.lastname: Illarionova
authors.forename: Boris
authors.initials: B
authors.lastname: Illarionov
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.forename: Robert
authors.initials: R
authors.lastname: Huber
authors.forename: Arne
authors.initials: A
authors.lastname: Skerra
authors.forename: Adelbert
authors.initials: A
authors.lastname: Bacher
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019143:Evolution, Molecular; D008024:Ligands; D008164:Luminescent Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D055095:Optics and Photonics; D010776:Photobacterium / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D012256:Riboflavin / Q000378:metabolism; D012258:Riboflavin Synthase / Q000737:chemistry / Q000378:metabolism; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; D008164:Luminescent Proteins; D021122:Protein Subunits; C026648:lumazine protein, Photobacterium; D012258:Riboflavin Synthase; D012256:Riboflavin