title: Structural identification of autoinducer of Photobacterium fischeri luciferase.
abstract: Synthesis of bacterial luciferase in some strains of luminous bacteria requires a threshold concentration of an autoinducer synthesized by the bacteria and excreted into the medium. Autoinducer excreted by Photobacterium fischeri strain MJ-1 was isolated from the cell-free medium by extraction with ethyl acetate, evaporation of solvent, workup with ethanol-water mixtures, and silica gel chromatography, followed by normal-phase and then reverse-phase high-performance liquid chromatography. The final product was greater than 99% pure. The structure of the autoinducer as determined by high-resolution 1H nuclear magnetic resonance spectroscopy, infrared spectroscopy, and high-resolution mass spectrometry was N-(3-oxohexanoly)-3-aminodihydro-2(3H)-furanone [or N-(beta-ketocaproyl)homoserine lactone]. The formation of homoserine by hydrolysis of the autoinducer was consistent with this structure. Synthetic autoinducer, obtained as a racemate, was prepared by coupling homoserine lactone to the ethylene glycol ketal of sodium 3-oxohexanoate, followed by mildly acidic removal of the protecting group; this synthetic material showed the appropriate biological activity.
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000502:physiology*; D004790:Enzyme Induction; D005663:Furans / Q000502:physiology*; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis*; D008163:Luminescent Measurements; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010776:Photobacterium / Q000201:enzymology*
chemical_list: D005663:Furans; C030654:N-(3-oxohexanoyl)-3-aminodihydro-2(3H)-furanone; D008156:Luciferases; D015107:4-Butyrolactone