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Results for “Firefly Luciferin”

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PubMed2003

A mutagenesis study of the putative luciferin binding site residues of firefly luciferase.

Firefly luciferase catalyzes the highly efficient emission of yellow-green light from substrate firefly luciferin by a sequence of reactions that require Mg-ATP and molecular oxygen. We had previously developed [Branchini, B. R., Magyar, R. A., Murtiashaw, M. H., Anderson, S. M., and Zimmer, M. (1998) Biochemistry 37, 15311-15319] a molecular graphics-based working model of the luciferase active site starting with the first X-ray structure [Conti, E., Franks, N. P., and Brick, P. (1996) Structure 4, 287-298] of the enzyme without bound substrates. In our model, the luciferin binding site contains 15 residues that are within 5 A of the substrate. Using site-directed mutagenesis, we made changes at all of these residues and report here the characterization of the corresponding expressed and purified proteins. Of the 15 residues studied, 12 had a significantly (>or=4-fold K(m) difference) altered binding affinity for luciferin and seven residues, spanning the primary sequence region Arg218-Ala348, had substantially (>or=30 nm) red-shifted bioluminescence emission maxima when mutated. We report here an interpretation of the roles of the mutated residues in substrate binding and bioluminescence color determination. The results of this study generally substantiate the accuracy of our model and provide the foundation for future experiments designed to alter the substrate specificity of firefly luciferase.

Animals↗
PubMed1988

Clinical and biochemical applications of luciferases and luciferins.

Recent advances in the analytical applications of bacterial and firefly luciferases and firefly luciferin are reviewed. Luciferases have been used in soluble and immobilized/co-immobilized forms in assays for a variety of enzymes, substrates, and cofactors. The firefly luciferase reaction forms the basis of rapid microbiological tests which have found application in susceptibility testing, detection of bacteriuria, activated sludge analysis, and food testing. Rapid microbiological assays are also possible using bacteriophages containing the lux genes from Virbrio harveyi. Both the firefly and the bacterial luciferase reaction have been applied in immunoassay and DNA probe assays and the firefly luciferin phosphate substrate for alkaline phosphatase labels has proven particularly successful.

Adenosine Triphosphate↗
PubMed2003

Firefly luciferin-activated rose bengal: in vitro photodynamic therapy by intracellular chemiluminescence in transgenic NIH 3T3 cells.

Photodynamic therapy (PDT) of cancer (1, 2) is a well-established treatment modality that uses light excitation of a photosensitive substance to produce oxygen-related cytotoxic intermediates, such as singlet oxygen or free radicals (3, 4). Although PDT is advantageous over other forms of cancer treatments because of its limited side effects, its main disadvantage is the poor accessibility of light to more deeply lying malignancies. External light sources such as lasers or lamps can be applied either noninvasively to reach tumors that lie well within the penetration depth of the light or in a minimally invasive fashion (interstitial treatments) in which optical fibers are placed intratumorally through needles. Even with the second approach, light distribution over the tumor is not homogeneous and nonidentified metastatic disease is left untreated. CL, the chemical production of light, is exemplified by firefly light emission mediated by the enzymatic (luciferase + ATP) oxidation of D-luciferin to oxyluciferin (5). This mobile light source is a targetable alternative to external sources of illumination. Here we show the in vitro photodynamic effect of rose bengal activated by intracellular generation of light, in luciferase-transfected NIH 3T3 murine fibroblasts.

3T3 Cells↗
PubMed1991

Probing the molecular dimensions of general anaesthetic target sites in tadpoles (Xenopus laevis) and model systems using cycloalcohols.

1. The series of cycloalcohols C6, C7, C8 and C10 have been used to probe the molecular dimensions of a variety of general anaesthetic target sites. 2. The general anaesthetic EC50 concentrations of the cycloalcohols were determined for tadpoles (Xenopus laevis). All of the cycloalcohols tested were found to be potent general anaesthetics (on average EC50/Csat = 0.03). 3. The effects of the cycloalcohols on highly purified luciferase enzymes from fireflies (Photinus pyralis) and bacteria (Vibrio harveyi) were also investigated. Both enzymes were inhibited competitively, with the cycloalcohols competing with firefly luciferin for binding to the firefly enzyme and with n-decanal for binding to the bacterial enzyme. 4. The binding site on the firefly enzyme could accommodate two molecules of cycloalcohols C6 and C7 but only a single molecule of the larger cycloalcohols (C8 and C10), implying a volume of the binding site of about 250 cm3 mol-1. In contrast, the binding site on the bacterial luciferase could bind only a single cycloalcohol molecule between C6 and C10. 5. While all of the cycloalcohols were potent inhibitors of the firefly luciferase enzyme (on average EC50/Csat = 0.015), they were very weak inhibitors of the bacterial luciferase enzyme (on average EC50/Csat = 0.12). Since both enzymes bind long-chain aliphatic n-alcohols tightly, the differing affinities of the cycloalcohols for the two enzymes is probably a consequence of geometrical factors. 6. The cycloalcohols produced very small effects on lipid bilayers. At EC50 concentrations which produce general anaesthesia, lipid bilayer phase transitions were shifted, on average, by only 0.43 degrees C. 7. We conclude that the general anaesthetic effects of the cycloalcohols can most economically be explained by assuming that the cycloalcohols act at protein binding sites in the central nervous system. These target sites would have binding properties similar to those of the anaesthetic-binding site on firefly luciferase, but their average volume would be somewhat smaller than 250 cm3 mol -1.

Alcohols↗
PubMed2005

Firefly luciferase exhibits bimodal action depending on the luciferin chirality.

Firefly luciferase is able to convert L-luciferin into luciferyl-CoA even under ordinary aerobic luciferin-luciferase reaction conditions. The luciferase is able to recognize strictly the chirality of the luciferin structure, serving as the acyl-CoA synthetase for L-luciferin, whereas d-luciferin is used for the bioluminescence reaction. D-Luciferin inhibits the luciferyl-CoA synthetase activity of L-luciferin, whereas L-luciferin retards the bioluminescence reaction of D-luciferin, meaning that both enzyme activities are prevented by the enantiomer of its own substrate.

Acyl Coenzyme A↗
PubMed1991

Analogs and derivatives of firefly oxyluciferin, the light emitter in firefly bioluminescence.

The 5-methyl analog of firefly oxyluciferin, two isomeric O-methyl ether derivatives of it and an O,O'-dimethyl ether derivative were synthesized and their UV absorption and fluorescence emission spectra were determined. Comparisons of the emission data with the emission wavelength in bioluminescence indicate that the mono-anions of firefly oxyluciferin are candidates for the light-emitters in bioluminescence. Further, we have found that the chemiluminescence of active esters of firefly luciferin produces (from the keto form of oxyluciferin) only red light emission under a variety of conditions; a yellow-green light emission (from the enolic forms of the oxyluciferin product) could not be elicited.

Animals↗
PubMed1984

Enhanced luminescent enzyme immunoassays for rubella antibody, immunoglobulin E and digoxin.

A novel firefly luciferin- enhanced luminescent procedure for the quantitation of horseradish peroxidase labels has been directly incorporated into established enzyme immunoassays. The procedure is rapid and sensitive and uses readily available reagents. Light emission from the enhanced reaction is high and relatively constant and thus easily measured. The luminescence procedure has been successfully incorporated into immunometric assays for rubella antibody and human IgE and into a competitive immunoassay for digoxin.

Animals↗
PubMed1991

Mapping the polarity profiles of general anesthetic target sites using n-alkane-(alpha, omega)-diols.

The effects of the homologous series of n-alkane-(alpha, omega)-diols have been studied on the inhibition of the purified firefly luciferase enzyme from Photinus pyralis, the inhibition of the purified bacterial luciferase enzyme from Vibrio harveyi, and the induction of general anesthesia in Xenopus laevis tadpoles. All but one of the diols tested were found to be reversible general anesthetics. The diols inhibited firefly luciferase by competing with its normal substrate firefly luciferin, and they inhibited bacterial luciferase by competing with the substrate n-decanal. For all but the smallest agent (1,4-butanediol), only a single diol molecule was found to be involved in the inhibition of the enzymes. Inhibition constants Ki were determined for the enzymes, and general anesthetic EC50 concentrations were determined for tadpoles. These data were then used in conjunction with previously determined n-alkane and n-alcohol data to calculate, as a function of chain length, the incremental standard Gibbs free energies delta (delta G0) for adding apolar -CH2- groups and for converting apolar terminal -CH3 groups to polar -CH2OH groups. The resulting plots of delta (delta G0) versus chain length gave a consistent mapping of the polarity profiles of the anesthetic-binding pockets. They clearly reveal the existence of two substantial and distinct polar regions in the anesthetic-binding pocket of firefly luciferase but only one such region for bacterial luciferase and for the unknown target sites underlying general anesthesia. The polarities and geometric properties of these different binding sites for straight-chain anesthetics are discussed in terms of simple models.

Anesthetics↗
PubMedDate not supplied

Inactivation of firefly luciferase and rat erythrocyte ATPase by ultrasound.

Previous work in our laboratories has shown that, amongst other effects, irradiation of frog skin with low intensity ultrasound causes reductions in the chemical driving force of the short-circuit current. This indicated that either the Na/K dependent ATPase or ATP availability were being reduced. We measured the effect of ultrasound irradiation on ATP and NA/K-dependent ATPase from inverted erythrocyte ghosts and on firefly luciferin and luciferase activity. Our findings demonstrate that ultrasonic cavitation-induced sonochemical reactions were responsible for irreversible inactivation of luciferase and ATPase but had little or no effect on ATP and luciferin. We measured the levels of hydrogen peroxide generated by ultrasound under the conditions of our experiments and found that it could account for only part of the enzyme inactivation observed. Free radical scavengers/antioxidants were capable of fully protecting the enzymes from ultrasound-induced inactivation. These findings demonstrate that, in addition to hydrogen peroxide, free radicals generated by ultrasound are responsible for the effects.

Adenosine Triphosphatases↗
PubMed1982

Analysis of the disagreement between automated bioluminescence-based and culture methods for detecting significant bacteriuria, with proposals for standardizing evaluations of bacteriuria detection methods.

A fully automated method for detecting significant bacteriuria is described which uses firefly luciferin and luciferase to detect bacterial ATP in urine. The automated method was calibrated and evaluated, using 308 urine specimens, against two reference culture methods. We obtained a specificity of 0.79 and sensitivity of 0.75 using a quantitative pour plate reference test and a specificity of 0.79 and a sensitivity of 0.90 using a semiquantitative standard loop reference test. The majority of specimens negative by the automated test but positive by the pour plate reference test were specimens which grew several bacterial species. We suggest that such disagreement was most likely for urine containing around 10(5) colony-forming units per ml (the culture threshold of positivity) and that these specimens were ones contaminated by urethral or vaginal flora. We propose standard procedures for calibrating and evaluating rapid or automated methods for the detection of significant bacteriuria and have analyzed our results using these procedures. We recommend that identical analyses should be reported for other evaluations of bacteriuria detection methods.

Adenosine Triphosphate↗
PubMed1981

The assay of adenosine 5'-triphosphate extracted from salt-marsh microbiota.

The light-emitting reaction of firefly luciferin and luciferase is a common ingredient in the quantification of adenosine triphosphate (ATP) extracted from the microbiota of environmental samples. Both portions of the light-emission phase of the luciferase reaction, the primary flash within 3 s of mixing and the secondary decay in the luminescence following the flash, have been used to quantify extracted ATP. However, the magnitude of the secondary phase is influenced by nucleotides other than ATP. The impact of this influence on the quantification of ATP was studied in samples collected from the water covering a salt marsh. Analysis by integration of the secondary decay portion of the emission yielded values of ATP per cubic metre that were consistently higher than those obtained by peak height analysis of the same extracts. Assays using the integration technology resulted in values that were up to 8 (mean = 3.6) times higher than corresponding values determined by peak height analysis in unfractionated samples (total microbial biomass) and up to 16 (mean = 4.8) times higher in water that had been prefiltered with a 1.0 micrometer filter (bacterial biomass).

Adenosine Triphosphate↗
PubMed1976

Molecular mechanism of inhibition of firefly luminescence by local anesthetics.

The kinetics of the action of local anesthetics upon firefly luciferin and luciferase systems is presented. Clinical concentrations of local anesthetics inhibited this ATP-induced luminescence in a dose-dependent manner. From the effects of temperature and pH upon the inhibitory action of the local anesthetics, it is concluded that hydrophobic ligand-enzyme interaction is the predominant cause of the inhibition, but hydrophilic interaction also contributes to the inhibition to a lesser degree. A molecular theory of anesthesia is outlined which postulates that release of electrostricted water molecules from the hydrophilic parts of the enzyme due to the protein conformational changes induced by anesthetics is the cause of the decreased luminescence. A similar mechanism is expected to occur at the cell membrane, which probably dehydrates the sodium channel and suppresses the conductance of this ion across the membrane. These events lead to a volume expansion of the total system, and the system becomes reactive to a pressure which reverses the anesthesia by shifting the equilibrium to the nonanesthetized original volume. The pressure antagonism of anesthesia can be explained by this overall volume expansion and not by a mere swelling of the cell membrane.

Anesthetics, Local↗
PubMed2006

Stereoisomeric bio-inversion key to biosynthesis of firefly D-luciferin.

The chirality of the luciferin substrate is critical to the luciferin-luciferase reaction producing bioluminescence. In firefly, the biosynthetic pathway of D-luciferin is still unclear, although it can be synthesized in vitro from D-cysteine. Here, we show that the firefly produces both D- and L-luciferin, and that the amount of active D-luciferin increases gradually with maturation stage. Studies of firefly body extracts indicate the possible conversion of L-cysteine via L-luciferin into D-luciferin, suggesting that the biosynthesis is enzymatically regulated by stereoisomeric bio-inversion of L-luciferin. We conclude that the selection of chirality in living organisms is not as rigid as previously thought.

Animals↗
PubMed1984

alpha-Bungarotoxin-luciferin as a bioluminescent probe for characterization of acetylcholine receptors in the central nervous system.

Firefly luciferin, a substrate for luciferase-catalyzed light emission, has been covalently linked to alpha-bungarotoxin (alpha-BTX) and shown to be an extremely sensitive nonradioactive probe to study nicotinic acetylcholine receptors. The concentration of nicotinic receptors was measured in several regions of the rat brain, with highest concentrations present in hypothalamus and cerebral cortex. Using rat cerebral cortex homogenate, it was determined that alpha-BTX-luciferin binding is saturable with a high affinity (apparent KD = 0.43 nM) and low capacity (42 fmol/mg of protein). The specificity of alpha-BTX-luciferin binding was demonstrated by the ability of various cholinergic agonists and antagonists to inhibit binding. alpha-BTX, lobeline (a cholinergic agonist) and d-tubocurarine (a nicotinic antagonist) are the most potent inhibitors of specific alpha-BTX-luciferin binding (inhibition constant, KI = 0.12, 60, and 60 nM, respectively). Scopolamine, a muscarinic antagonist, is the least potent inhibitor examined (KI greater than 10 mM). The sensitivity of this assay to detect alpha-BTX-luciferin is approximately 3 X 10(-17) mol and allows us to measure alpha-BTX-luciferin binding to tissue samples containing less than 10 micrograms of protein. This represents an approximate 50-fold increase of sensitivity over conventional ligand-receptor assays using 125I-alpha-BTX. These results provide the basis for an ultrasensitive assay using nonradioactive probes in the quantitation of nicotinic acetylcholine receptors. Conjugation of luciferin to other molecules will lead to the development of sensitive bioluminescent immuno- and receptor assays.

Animals↗
PubMed2006

Cloning and characterization of the homologous genes of firefly luciferase in the mealworm beetle, Tenebrio molitor.

Three homologous genes of firefly luciferase were cloned from the non-luminous beetle Tenebrio molitor. Three gene products for homologues, TmLL-1, TmLL-2 and TmLL-3, showed fatty acyl-coenzyme A (acyl-CoA) synthetic activity, but not luciferase activity with firefly luciferin. The transcripts were detected through the developmental stages in T. molitor. These results suggested that firefly luciferase was evolved from a fatty acyl-coenzyme A synthetase by gene duplications in the insect.

Amino Acid Sequence↗