Firefly luciferase can use L-luciferin to produce light

Caged aminoluciferin probe for bioluminescent immunoproteasome activity analysis

The immunoproteasome (iCP) can be expressed under inflammatory conditions, such as exposure to interferon-gamma (IFN-γ), that alerts the cell to begin generating iCP preferentially over the standard proteasome (sCP). With the iCP becoming a widely targeted isoform in a variety of diseases, there is a need to understand its activity and expression in cells and in vivo. Activity-based probes for the iCP have been developed but their application has been limited due to their difficult synthesis and cannot be used in tissues or whole animals. Our lab has previously demonstrated we can monitor iCP activity using a 4-mer peptide linked to a fluorophore and a peptoid. This was utilized in the development of the first cell-permeable iCP activity-based probe that did not include a covalent reactive moiety. Here, we demonstrate that this same peptide recognition sequence can be appended to aminoluciferin, caging it, until its interaction with the iCP. This probe should be applicable to monitor iCP activity in animal models where tumor or other tissue has been engineered to produce luciferase. We anticipate it could also be applied to observe iCP activity as tumors are formed in vivo.

Genome assembly of Genji firefly (Nipponoluciola cruciata) reveals novel luciferase-like luminescent proteins without peroxisome targeting signal

The Genji firefly, Nipponoluciola cruciata, is an aquatic firefly endemic to Japan, inhabiting a wide area of the Japanese archipelago. The luminescence of fireflies is a scientifically interesting phenomenon, and many studies have evaluated this species in Japan. In this study, we sequenced the whole genome of male N. cruciata and constructed a high-quality genome assembly of 662 Mb with a BUSCO completeness of 99.1% in the genome mode. Using the detected set of 15,169 protein-coding genes, the genomic structures and genetic background of luminescence-related genes were also investigated. We found four new firefly luciferase-like genes in the genome. The highest bioluminescent activity was observed for LLa2, which originated from ancestral PDGY, a mitochondrial acyl-CoA synthetase. A thioesterase candidate, NcruACOT1, which is involved in d-luciferin biosynthesis, was expressed in the lantern. Two opsins were also detected and the absorption wavelength of the UV-type opsin candidate shifted from UV to blue. These findings provide an important resource for unravelling the adaptive evolution of fireflies in terms of luminescence and vision.

Bioluminescence of (R)-Cypridina Luciferin with Cypridina Luciferase

Cypridina luciferin (CypL) is a marine natural product that functions as the luminous substrate for the enzyme Cypridina luciferase (CypLase). CypL has two enantiomers, (R)- and (S)-CypL, due to its one chiral center at the sec-butyl moiety. Previous studies reported that (S)-CypL or racemic CypL with CypLase produced light, but the luminescence of (R)-CypL with CypLase has not been investigated. Here, we examined the luminescence of (R)-CypL, which had undergone chiral separation from the enantiomeric mixture, with a recombinant CypLase. Our luminescence measurements demonstrated that (R)-CypL with CypLase produced light, indicating that (R)-CypL must be considered as the luminous substrate for CypLase, as in the case of (S)-CypL, rather than a competitive inhibitor for CypLase. Additionally, we found that the maximum luminescence intensity from the reaction of (R)-CypL with CypLase was approximately 10 fold lower than that of (S)-CypL with CypLase, but our kinetic analysis of CypLase showed that the Km value of CypLase for (R)-CypL was approximately 3 fold lower than that for (S)-CypL. Furthermore, the chiral high-performance liquid chromatography (HPLC) analysis of the reaction mixture of racemic CypL with CypLase showed that (R)-CypL was consumed more slowly than (S)-CypL. These results indicate that the turnover rate of CypLase for (R)-CypL was lower than that for (S)-CypL, which caused the less efficient luminescence of (R)-CypL with CypLase.

Biosynthesis-Inspired Deracemizative Production of D-Luciferin In Vitro by Combining Luciferase and Thioesterase

Due to the strict enantioselectivity of firefly luciferase (FLuc), only D-luciferin can be used as a substrate for the bioluminescence (BL) reaction. Unfortunately, luciferin racemizes easily and accumulation of nonluminous L-luciferin has negative influences on the light-emitting reaction. By a detailed analysis of luciferin chirality, however, it becomes clarified that L-luciferin is the biosynthetic precursor of D-luciferin in fireflies and undergoes the enzymatic chiral inversion. By the chiral inversion reaction, the enantiopurity of luciferin can be maintained in the reaction mixture for applications using FLuc. Thus, chirality is crucial for the BL reaction and essential for investigating and applying the biosynthesis of D-luciferin. Here, we describe the methods for the analysis of chiral inversion reaction using high-performance liquid chromatography (HPLC) with a chiral column. We also introduce an example of an in vitro deracemizative BL reaction system using a combination of FLuc and fatty acyl-CoA thioesterase, which is inspired by the chiral inversion mechanism in the biosynthetic pathway of D-luciferin.

Luciferin Regeneration in Firefly Bioluminescence via Proton-Transfer-Facilitated Hydrolysis, Condensation and Chiral Inversion

Firefly bioluminescence is produced via luciferin enzymatic reactions in luciferase. Luciferin has to be unceasingly replenished to maintain bioluminescence. How is the luciferin reproduced after it has been exhausted? In the early 1970s, Okada proposed the hypothesis that the oxyluciferin produced by the previous bioluminescent reaction could be converted into new luciferin for the next bioluminescent reaction. To some extent, this hypothesis was evidenced by several detected intermediates. However, the detailed process and mechanism of luciferin regeneration remained largely unknown. For the first time, we investigated the entire process of luciferin regeneration in firefly bioluminescence by density functional theory calculations. This theoretical study suggests that luciferin regeneration consists of three sequential steps: the oxyluciferin produced from the last bioluminescent reaction generates 2-cyano-6-hydroxybenzothiazole (CHBT) in the luciferin regenerating enzyme (LRE) via a hydrolysis reaction; CHBT combines with L-cysteine in vivo to form L-luciferin via a condensation reaction; and L-luciferin inverts into D-luciferin in luciferase and thioesterase. The presently proposed mechanism not only supports the sporadic evidence from previous experiments but also clearly describes the complete process of luciferin regeneration. This work is of great significance for understanding the long-term flashing of fireflies without an in vitro energy supply.

An allylated firefly luciferin analogue with luciferase specific response in living cells

An allylated firefly luciferin was successfully synthesized and its bioluminescence properties were evaluated. When applied to cellular imaging in combination with Eluc, which is one of the commercially available luciferases, this analogue displayed a luciferase-specific bioluminescence signal with prolonged emission (>100 min).

Transcriptome analysis reveals candidate genes involved in luciferin metabolism in Luciola aquatilis (Coleoptera: Lampyridae)

Bioluminescence, which living organisms such as fireflies emit light, has been studied extensively for over half a century. This intriguing reaction, having its origins in nature where glowing insects can signal things such as attraction or defense, is now widely used in biotechnology with applications of bioluminescence and chemiluminescence. Luciferase, a key enzyme in this reaction, has been well characterized; however, the enzymes involved in the biosynthetic pathway of its substrate, luciferin, remains unsolved at present. To elucidate the luciferin metabolism, we performed a de novo transcriptome analysis using larvae of the firefly species, Luciola aquatilis. Here, a comparative analysis is performed with the model coleopteran insect Tribolium casteneum to elucidate the metabolic pathways in L. aquatilis. Based on a template luciferin biosynthetic pathway, combined with a range of protein and pathway databases, and various prediction tools for functional annotation, the candidate genes, enzymes, and biochemical reactions involved in luciferin metabolism are proposed for L. aquatilis. The candidate gene expression is validated in the adult L. aquatilis using reverse transcription PCR (RT-PCR). This study provides useful information on the bio-production of luciferin in the firefly and will benefit to future applications of the valuable firefly bioluminescence system.

One-pot non-enzymatic formation of firefly luciferin in a neutral buffer from p-benzoquinone and cysteine

Firefly luciferin, the substrate for the bioluminescence reaction of luminous beetles, possesses a benzothiazole ring, which is rare in nature. Here, we demonstrate a novel one-pot reaction to give firefly luciferin in a neutral buffer from p-benzoquinone and cysteine without any synthetic reagents or enzymes. The formation of firefly luciferin was low in yield in various neutral buffers, whereas it was inhibited or completely prevented in acidic or basic buffers, in organic solvents, or under a nitrogen atmosphere. Labelling analysis of the firefly luciferin using stable isotopic cysteines showed that the benzothiazole ring was formed via the decarboxylation and carbon-sulfur bond rearrangement of cysteine. These findings imply that the biosynthesis of firefly luciferin can be developed/evolved from the non-enzymatic production of firefly luciferin using common primary biosynthetic units, p-benzoquinone and cysteine.

Luciferin-Regenerating Enzyme Mediates Firefly Luciferase Activation Through Direct Effects of D-Cysteine on Luciferase Structure and Activity

Luciferin-regenerating enzyme (LRE) contributes to in vitro recycling of D-luciferin. In this study, reinvestigation of the luciferase-based LRE assay is reported. Here, using quick change site-directed mutagenesis seven T-LRE (Lampyris turkestanicusLRE) mutants were constructed and the most functional mutant of T-LRE (T(69)R) was selected for this research and the effects of D- and L-cysteine on T(69)R T-LRE-luciferase-coupled assay are examined. Our results demonstrate that bioluminescent signal of T(69)R T-LRE-luciferase-coupled assay increases and then reach equilibrium state in the presence of 5 mm D-cysteine. In addition, results reveal that 5 mm D- and L-cysteine in the absence of T(69)R T-LRE cause a significant increase in bioluminescence intensity of luciferase over a long time as well as decrease in decay rate. Based on activity measurements, far-UV CD analysis, ANS fluorescence and DLS (Dynamic light scattering) results, D-cysteine increases the activity of luciferase due to weak redox potential, antiaggregatory effects, induction of changes in conformational structure and kinetics properties. In conclusion, in spite of previous reports on the effect of LRE on luciferase bioluminescent intensity, the majority of increase in luciferase light output and time-course originate from the direct effects of D-cysteine on structure and activity of firefly luciferase.

Multimodality imaging methods for assessing retinoblastoma orthotopic xenograft growth and development

Genomic studies of the pediatric ocular tumor retinoblastoma are paving the way for development of targeted therapies. Robust model systems such as orthotopic xenografts are necessary for testing such therapeutics. One system involves bioluminescence imaging of luciferase-expressing human retinoblastoma cells injected into the vitreous of newborn rat eyes. Although used for several drug studies, the spatial and temporal development of tumors in this model has not been documented. Here, we present a new model to allow analysis of average luciferin flux ([Formula: see text]) through the tumor, a more biologically relevant parameter than peak bioluminescence as traditionally measured. Moreover, we monitored the spatial development of xenografts in the living eye. We engineered Y79 retinoblastoma cells to express a lentivirally-delivered enhanced green fluorescent protein-luciferase fusion protein. In intravitreal xenografts, we assayed bioluminescence and computed [Formula: see text], as well as documented tumor growth by intraocular optical coherence tomography (OCT), brightfield, and fluorescence imaging. In vivo bioluminescence, ex vivo tumor size, and ex vivo fluorescent signal were all highly correlated in orthotopic xenografts. By OCT, xenografts were dense and highly vascularized, with well-defined edges. Small tumors preferentially sat atop the optic nerve head; this morphology was confirmed on histological examination. In vivo, [Formula: see text] in xenografts showed a plateau effect as tumors became bounded by the dimensions of the eye. The combination of [Formula: see text] modeling and in vivo intraocular imaging allows both quantitative and high-resolution, non-invasive spatial analysis of this retinoblastoma model. This technique will be applied to other cell lines and experimental therapeutic trials in the future.

Biosynthesis of firefly luciferin in adult lantern: decarboxylation of L-cysteine is a key step for benzothiazole ring formation in firefly luciferin synthesis

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 ᴅ-form in 1963 and studies on the biosynthesis of firefly luciferin began early in the 1970’s. Incorporation experiments using ¹⁴C-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.

Methodology/Principal Findings

Incorporation studies were performed by injecting stable isotope-labeled compounds, including ʟ-[U-¹³C₃]-cysteine, ʟ-[1-¹³C]-cysteine, ʟ-[3-¹³C]-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 ᴅ- and ʟ-firefly luciferins are biosynthesized in the lantern of the adult firefly from two ʟ-cysteine molecules with p-benzoquinone/1,4-hydroquinone, accompanied by the decarboxylation of ʟ-cysteine.

Bioluminescence imaging of therapy response does not correlate with FDG-PET response in a mouse model of Burkitt lymphoma

Since the development and evaluation of novel anti-cancer therapies require molecular insight in the disease state, both FDG-PET and BLI imaging were evaluated in a Burkitt B-cell lymphoma xenograft model treated with cyclophosphamide or temsirolimus. Daudi xenograft mice were treated with either cyclophosphamide or temsirolimus and imaged with BLI and FDG-PET on d0 (before treatment), d2, d4, d7, d9 and d14 following the start of therapy. Besides tumor volume changes, therapy response was assessed with immunohistochemical analysis (apoptosis). BLI revealed a flare following both therapeutics that was significantly higher when compared to control tumors. FDG-PET decreased immediatelly, long before the tumor reduced in size. Late after therapy, BLI signal intensities decreased significantly compared to baseline subsequent to tumor size reduction while apoptosis was immediately induced following both treatment regimen. Unlike FDG, BLI was not able to reflect reduced levels of viable cells and was not able to predict tumor size response and apoptosis response.

A selenium analogue of firefly D-luciferin with red-shifted bioluminescence emission

A selenium analogue of amino-D-luciferin, aminoseleno-D-luciferin, is synthesized and shown to be a competent substrate for the firefly luciferase enzyme. It has a red-shifted bioluminescence emission maximum at 600 nm and is suitable for bioluminescence imaging studies in living subjects.

Kinetics of inhibition of firefly luciferase by dehydroluciferyl-coenzyme A, dehydroluciferin and L-luciferin

The inhibition mechanisms of the firefly luciferase (Luc) by three of the most important inhibitors of the reactions catalysed by Luc, dehydroluciferyl-coenzyme A (L-CoA), dehydroluciferin (L) and L-luciferin (L-LH(2)) were investigated. Light production in the presence and absence of these inhibitors (0.5 to 2 μM) has been measured in 50 mM Hepes buffer (pH = 7.5), 10 nM Luc, 250 μM ATP and D-luciferin (D-LH(2), from 3.75 up to 120 μM). Nonlinear regression analysis with the appropriate kinetic models (Henri-Michaelis-Menten and William-Morrison equations) reveals that L-CoA is a non-competitive inhibitor of Luc (K(i) = 0.88 ± 0.03 μM), L is a tight-binding uncompetitive inhibitor (K(i) = 0.00490 ± 0.00009 μM) and L-LH(2) acts as a mixed-type non-competitive-uncompetitive inhibitor (K(i) = 0.68 ± 0.14 μM and αK(i) = 0.34 ± 0.16 μM). The K(m) values obtained for L-CoA, L and L-LH(2) were 16.1 ± 1.0, 16.6 ± 2.3 and 14.4 ± 0.96 μM, respectively. L and L-LH(2) are strong inhibitors of Luc, which may indicate an important role for these compounds in Luc characteristic flash profile. L-CoA K(i) supports the conclusion that CoA can stimulate the light emission reaction by provoking the formation of a weaker inhibitor.

Firefly luciferase: an adenylate-forming enzyme for multicatalytic functions

Firefly luciferase is a member of the acyl-adenylate/thioester-forming superfamily of enzymes and catalyzes the oxidation of firefly luciferin with molecular oxygen to emit light. Knowledge of the luminescence mechanism catalyzed by firefly luciferase has been gathered, leading to the discovery of a novel catalytic function of luciferase. Recently, we demonstrated that firefly luciferase has a catalytic function of fatty acyl-CoA synthesis from fatty acids in the presence of ATP, Mg(2+) and coenzyme A. Based on identification of fatty acyl-CoA genes in firefly, Drosophila, and non-luminous click beetles, we then proposed that the evolutionary origin of firefly luciferase is a fatty acyl-CoA synthetase in insects. Further, we succeeded in converting the fatty acyl-CoA synthetase of non-luminous insects into functional luciferase showing luminescence activity by site-directed mutagenesis.

Firefly bioluminescence: a mechanistic approach of luciferase catalyzed reactions

Luciferase is a general term for enzymes catalyzing visible light emission by living organisms (bioluminescence). The studies carried out with Photinus pyralis (firefly) luciferase allowed the discovery of the reaction leading to light production. It can be regarded as a two-step process: the first corresponds to the reaction of luciferase's substrate, luciferin (LH(2)), with ATP-Mg(2+) generating inorganic pyrophosphate and an intermediate luciferyl-adenylate (LH(2)-AMP); the second is the oxidation and decarboxylation of LH(2)-AMP to oxyluciferin, the light emitter, producing CO(2), AMP, and photons of yellow-green light (550- 570 nm). In a dark reaction LH(2)-AMP is oxidized to dehydroluciferyl-adenylate (L-AMP). Luciferase also shows acyl-coenzyme A synthetase activity, which leads to the formation of dehydroluciferyl-coenzyme A (L-CoA), luciferyl-coenzyme A (LH(2)-CoA), and fatty acyl-CoAs. Moreover luciferase catalyzes the synthesis of dinucleoside polyphosphates from nucleosides with at least a 3'-phosphate chain plus an intact terminal pyrophosphate moiety. The LH(2) stereospecificity is a particular feature of the bioluminescent reaction where each isomer, D-LH(2) or L-LH(2), has a specific function. Practical applications of the luciferase system, either in its native form or with engineered proteins, encloses the analytical assay of metabolites like ATP and molecular biology studies with luc as a reporter gene, including the most recent and increasing field of bioimaging.

A basis for reduced chemical library inhibition of firefly luciferase obtained from directed evolution

We measured the "druggability" of the ATP-dependent luciferase derived from the firefly Photuris pennsylvanica that was optimized using directed evolution (Ultra-Glo, Promega). Quantitative high-throughput screening (qHTS) was used to determine IC(50)s of 198899 samples against a formulation of Ultra-Glo luciferase (Kinase-Glo). We found that only 0.1% of the Kinase-Glo inhibitors showed an IC(50) < 10 microM compared to 0.9% found from a previous qHTS against the firefly luciferase from Photinus pyralis (lucPpy). Further, the maximum affinity identified in the lucPpy qHTS was 50 nM, while for Kinase-Glo this value increased to 600 nM. Compounds with interactions stretching outside the luciferin binding pocket were largely lost with Ultra-Glo luciferase. Therefore, Ultra-Glo luciferase will show less compound interference when used as an ATP sensor compared to lucPpy. This study demonstrates the power of large-scale quantitative analysis of structure-activity relationships (>100K compounds) in addressing important questions such as a target's druggability.

alpha-Synuclein enhances bioluminescent activity of firefly luciferase by facilitating luciferin localization

alpha-Synuclein, the pathological component of Parkinson's disease, has been demonstrated to be highly interactive with various protein partners. alpha-Synuclein has been shown to exert a novel effect on the bioluminescence of firefly luciferase by stimulating the oxyluciferin formation from its substrate of luciferin, which results in a significant enhancement of the spike of flashing light via concomitant augmentation for both rapid rise and quick decay of the luminescence. Binding affinity between alpha-synuclein and luciferase was evaluated with K(d) of 8.1 microM based on a dose-dependent enhancement of the luciferase activity by alpha-synuclein. Kinetic analyses indicated that alpha-synuclein has facilitated luciferin localization to the luciferase by decreasing apparent K(m), which makes the maximum rate of bioluminescence no longer dependent upon ATP concentration. Catalytic consequences of the alpha-synuclein binding to luciferase have led to a delayed onset of the coenzyme A-mediated retardation of the quick decay of flashing light as well as a shift in the emission spectra of bioluminescence. Taken together, the novel effects of alpha-synuclein toward the bioluminescence of luciferase have been demonstrated to be initiated by the specific molecular interaction between the proteins which has influenced the substrate (luciferin) localization to the enzyme.

Firefly luminescence: a historical perspective and recent developments

Significant advances have occurred regarding our knowledge of firefly luciferase mechanisms. Although most of this progress was an outcome of molecular biology and structural studies, important achievements have also occurred on its fundamental chemistry. Those developments are here summarized and presented in a historical perspective.

Firefly luciferase produces hydrogen peroxide as a coproduct in dehydroluciferyl adenylate formation

Firefly luciferase catalyzes the synthesis of H2O2 from the same substrates as the bioluminescence reaction: ATP and luciferin (D-LH2). About 80% of the enzyme-bound intermediate D-luciferyl adenylate (D-LH2-AMP) is oxidized into oxyluciferin, and a photon is emitted during this reaction. The enzyme pathway responsible for the generation of H2O2 is a side reaction in which D-LH2-AMP is oxidized into dehydroluciferyl adenylate (L-AMP). Like the bioluminescence reaction, the luciferase-catalyzed synthesis of H2O2 and L-AMP is a stereospecific process, involving only the natural D enantiomer. However, the intramolecular electron transfer postulated as essential to the light emission process is not involved in this side reaction.

Stereoisomeric bio-inversion key to biosynthesis of fireflyd-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.

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.

Characterization of the interaction of P1,P4-diadenosine 5'-tetraphosphate with luciferase

Adenylated dinucleotides (Ap(n)A) are regulatory molecules that control various cellular processes. A very likely intracellular target for Ap(4)A are enzymes that require ATP as either substrate or modulator. We report the results of new biochemical studies aimed at characterizing the Ap(4)A interaction with firefly luciferase, by using the luminometric and thin layer chromatography techniques. The data presented herein demonstrate that Ap(4)A is a noncompetitive inhibitor for the ATP-induced luminescence. These results together with our previous findings that Ap(4)A is a luciferase substrate [Nucleosides Nucleotides Nucleic Acids 23 (2004) in press.] support the notion that, similar to its interaction with P(2) receptors, Ap(4)A also has a dual interaction with luciferase. Other Ap(n)As (n = 2, 5, and 6) also inhibited the ATP-luciferase interaction. Since Ap(n)As may have similar interactions with other intracellular ATP-requiring enzymes, the study presented herein validates ulterior investigations of the Ap(n)A interaction with such enzymes, and opens the way to a better understanding of their intracellular roles.

Synthesis of 7′-[ 123 I]iodo- d -luciferin for in vivo studies of firefly luciferase gene expression

D-(-)-2-(6'-hydroxy-7'-[(123)I]iodobenzothiazolyl)-delta(2)-thiazoline-4-caroxylic acid (7'-[(123)I]iodo-D-luciferin) was synthesized as a novel reporter probe for in vivo studies of firefly luciferase gene expression. 7'-Iodo-D-luciferin, a nonradioactive standard, was synthesized and showed the binding property (K(M)=4.28 microM) similar to that of D-luciferin (2.53 microM) for firefly luciferase in luminescence assay.

Molecular cloning and expression of a cDNA encoding the luciferase from the firefly, Pyrocoelia rufa

To clone a cDNA encoding the luciferase of the firefly, Pyrocoelia rufa, we have constructed a cDNA library and isolated the luciferase gene using PCR with gene specific primers. Sequence analysis of the cDNA encoding the luciferase of P. rufa revealed that the 1647 bp cDNA has an open reading frame of 548 amino acid residues. The deduced amino acid sequences of the luciferase gene of P. rufa showed 98.9% homology to that of P. miyako. Phylogenetic analysis further confirmed the deduced amino acid sequences of the P. rufa luciferase gene belonged to the same subfamily, Lampyrinae. Southern blot analysis suggested possible presence of the P. rufa luciferase gene as a single copy and Northern blot analysis confirmed light organ-specific expression pattern at the transcriptional level. The cDNA encoding the luciferase of P. rufa was expressed as a 69 kDa band in baculovirus-infected insect cells and the recombinant baculovirus-infected cell extracts emitted luminescence in the luciferase activity assay.

Firefly luciferase generates two low-molecular-weight light-emitting species

A bioluminescent D-luciferin-luciferase mixture is separated by gel filtration during the time course of the reaction. A simultaneous analysis with an UV-visible diode array detector and an on-line luminometer gives nonsuperimposable chromatograms. Luminescence recordings display three peaks, one associated with the enzyme (light-emitting species 1: LES(1)), and two other species free from the luciferase: LES(2), with a luciferyl-adenylate-like spectrum and LES(3). Production of these two species is nucleotide (ATP or 2'-dATP)- and pH-dependent. The chromatographic data presented here could lead to reconsideration of the generally assumed emission mechanism, which involves one emitter only. It could also suggest that each free emitting species is related to a colour of emission corresponding to the two defined wavelengths previously described ( approximately 575 and approximately 620 nm).

Gene transfer-mediated intracellular photodynamic therapy

The main limitation of photodynamic therapy is a very short penetrance length of the light in tissues. To overcome this shortcoming, a new method is proposed, where first a gene encoding protein luciferase is delivered using, e.g. adenovirus vector to the neoplastic cells and, after its expression, the photosensitizer, which should be activated, together with luciferin are injected to the organism. After their accumulation in the cancer cells, the photosensitizer activation is accomplished via light produced by chemiluminiscent reaction of luciferase and luciferin.

Bioluminescence as a possible auxiliary oxygen detoxifying mechanism in elaterid larvae

This work examines the hypothesis that beetle bioluminescent reactions may primarily have evolved to provide an auxiliary O2 detoxifying mechanism. The activities of antioxidant enzymes and of luciferase in the prothorax (bright) and abdomen (dim) of luminous larval Pyrearinus termitilluminans (Coleoptera: Elateridae) were measured after previous challenge with either hyperoxia, hypoxia, or the firefly luciferase inhibitor luciferin 6'-methyl ether (LME). Upon exposure to pure O2 for 72 h, the prothorax activities of total superoxide dismutase (SOD) and catalase were found to increase by 85% and 50%, respectively. Concomitantly, levels of luciferase and luciferin increased 80% and 50%. Assays of thiobarbituric acid reactive substances (TBARS) showed significantly augmented lipid peroxidation only in the abdomen (30%) where levels of antioxidant enzymes and especially luciferase are low. In contrast, exposure to hypoxia (2% O2) led to significant increases in prothorax citrate synthase (85%), succinate dehydrogenase (25%), and lactate dehydrogenase (30%) activities, but not in luciferase or antioxidant enzyme levels. LME administration alone decreased luciferase activities 20% but did not alter prothorax SOD activity. Prothorax SOD activity was increased by concomitant LME and hyperoxia treatments (30%), along with higher levels of TBARS (25%) and protein reactive carbonyl groups (50%). Altogether these data suggest that in elaterids, bioluminescence and reactions catalyzed by antioxidant enzymes may cooperate to minimize oxidative stress.

Time course of luciferyl adenylate synthesis in the firefly luciferase reaction

The time course of luciferyl adenylate formation in the reaction catalyzed by firefly luciferase (EC 1.13.12.7) has been followed. The properties of luciferyl adenylate, enzymatically or chemically synthesized, as substrate of luciferase, have been compared. The potential use of luciferyl adenylate for luciferase detection is here proposed.