title: Experimental Support for a Single Electron-Transfer Oxidation Mechanism in Firefly Bioluminescence.
abstract: Firefly luciferase produces light by converting substrate beetle luciferin into the corresponding adenylate that it subsequently oxidizes to oxyluciferin, the emitter of bioluminescence. We have confirmed the generally held notions that the oxidation step is initiated by formation of a carbanion intermediate and that a hydroperoxide (anion) is involved. Additionally, structural evidence is presented that accounts for the delivery of oxygen to the substrate reaction site. Herein, we report key convincing spectroscopic evidence of the participation of superoxide anion in a related chemical model reaction that supports a single electron-transfer pathway for the critical oxidative process. This mechanism may be a common feature of bioluminescence processes in which light is produced by an enzyme in the absence of cofactors.
authors.affiliation: †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Branchini
authors.affiliation: †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States.
authors.forename: Curran E
authors.initials: CE
authors.lastname: Behney
authors.affiliation: †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States.
authors.forename: Tara L
authors.initials: TL
authors.lastname: Southworth
authors.affiliation: †Department of Chemistry, Connecticut College, New London, Connecticut 06320, United States.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Fontaine
authors.affiliation: §Hauptman-Woodward Institute, Buffalo, New York 14203, United States.|∥Department of Structural Biology, University of Buffalo, Buffalo, New York 14203, United States.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Gulick
authors.affiliation: ‡Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Vinyard
authors.affiliation: ‡Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Brudvig
mesh_terms: D000818:Animals; D004579:Electron Transport; D004583:Electrons; D048888:Fireflies / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D049454:Firefly Luciferin / Q000737:chemistry / Q000378:metabolism; D049409:Luciferases, Firefly / Q000737:chemistry / Q000378:metabolism*; D049449:Luminescence; D008958:Models, Molecular; D010084:Oxidation-Reduction; D013481:Superoxides / Q000737:chemistry / Q000378:metabolism
chemical_list: D013481:Superoxides; D049454:Firefly Luciferin; D049409:Luciferases, Firefly