title: Biosynthesis of firefly luciferin in adult lantern: decarboxylation of L-cysteine is a key step for benzothiazole ring formation in firefly luciferin synthesis.
abstract: BACKGROUND
  Bioluminescence in fireflies and click beetles is produced by a luciferase-luciferin reaction. The luminescence property and protein structure of firefly luciferase have been investigated, and its cDNA has been used for various assay systems. The chemical structure of firefly luciferin was identified as the D-form in 1963 and studies on the biosynthesis of firefly luciferin began early in the 1970's. Incorporation experiments using (14)C-labeled compounds were performed, and cysteine and benzoquinone/hydroquinone were proposed to be biosynthetic component for firefly luciferin. However, there have been no clear conclusions regarding the biosynthetic components of firefly luciferin over 30 years.
  
  
  RESULTS
  Incorporation studies were performed by injecting stable isotope-labeled compounds, including L-[U-(13)C3]-cysteine, L-[1-(13)C]-cysteine, L-[3-(13)C]-cysteine, 1,4-[D6]-hydroquinone, and p-[2,3,5,6-D]-benzoquinone, into the adult lantern of the living Japanese firefly Luciola lateralis. After extracting firefly luciferin from the lantern, the incorporation of stable isotope-labeled compounds into firefly luciferin was identified by LC/ESI-TOF-MS. The positions of the stable isotope atoms in firefly luciferin were determined by the mass fragmentation of firefly luciferin.
  
  
  CONCLUSIONS
  We demonstrated for the first time that D- and L-firefly luciferins are biosynthesized in the lantern of the adult firefly from two L-cysteine molecules with p-benzoquinone/1,4-hydroquinone, accompanied by the decarboxylation of L-cysteine.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Oba
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshida
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
authors.forename: Shusei
authors.initials: S
authors.lastname: Kanie
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ojika
authors.affiliation: Yokohama Research Center, JNC Corporation, Yokohama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inouye
mesh_terms: D000818:Animals; D016227:Benzoquinones / Q000737:chemistry; D052160:Benzothiazoles / Q000737:chemistry*; D002853:Chromatography, Liquid; D003545:Cysteine / Q000737:chemistry*; D003653:Decarboxylation; D048888:Fireflies / Q000254:growth & development / Q000378:metabolism*; D049454:Firefly Luciferin / Q000378:metabolism*; D008163:Luminescent Measurements; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D016227:Benzoquinones; D052160:Benzothiazoles; C004532:quinone; D049454:Firefly Luciferin; C005465:benzothiazole; D003545:Cysteine