:Firefly luciferin
{{Short description|Chemical compound}}
{{Chembox
| ImageFile = File:Firefly Luciferin.svg
| ImageSize = 200px
| IUPACName = (4S)-2-(6-hydroxy-1,3-benzothiazol-2-yl)-4,5-dihydrothiazole-4-carboxylic acid
| OtherNames = D-(−)-Luciferin, beetle luciferin
|Section1={{Chembox Identifiers
| CASNo = 2591-17-5
| PubChem = 92934
| ChemSpiderID = 4588411
| ChemSpiderID1 = 16735812
| ChemSpiderID1_Comment = One of the other tautomeric representations
| EINECS = 219-981-3
| UNII = 5TBB02N29K
| InChI = InChI=1S/C11H8N2O3S2/c14-5-1-2-6-8(3-5)18-10(12-6)9-13-7(4-17-9)11(15)16/h1-3,7,13H,4H2,(H,15,16)/b10-9+/t7-/m1/s1
| InChI1 = InChI=1S/C11H8N2O3S2/c14-5-1-2-6-8(3-5)18-10(12-6)9-13-7(4-17-9)11(15)16/h1-3,7,14H,4H2,(H,15,16)/t7-/m1/s1
| InChI_Comment = One of the other tautomeric representations
| StdInChI=1S/C11H8N2O3S2/c14-5-1-2-6-8(3-5)18-10(12-6)9-13-7(4-17-9)11(15)16/h1-3,7,14H,4H2,(H,15,16)/t7-/m1/s1
| StdInChIKey = BJGNCJDXODQBOB-SSDOTTSWSA-N
| SMILES = O=C(O)[C@@H]1/N=C(\SC1)c2sc3cc(O)ccc3n2}}
|Section2={{Chembox Properties
| C=11 | H=8 | N=2 | O=3 | S=2
| Density =
| MeltingPt =
| BoilingPt =
| LambdaMax = 330 nm (neutral and somewhat acidic aqueous solutions) {{cite web |title=D-luciferin product information |url=https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Product_Information_Sheet/2/l9504pis.pdf |publisher=Sigma Aldrich}}
| Absorbance = ε330 = 18.2 mM−1 cm−1
| Solubility = }}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|315|319|335}}
| PPhrases = {{P-phrases|261|264|271|280|302+352|304+340|305+351+338|312|321|332+313|337+313|362|403+233|405|501}}
| MainHazards =
| FlashPt =
| AutoignitionPt = }}
}}
Firefly luciferin (also known as beetle luciferin) is the luciferin, precursor of the light-emitting compound, used for the firefly (Lampyridae), railroad worm (Phengodidae), starworm (Rhagophthalmidae), and click-beetle (Pyrophorini) bioluminescent systems.{{Cite journal |last=Schramm |first=Stefan |last2=Weiß |first2=Dieter |date=2024 |title=Bioluminescence – The Vibrant Glow of Nature and its Chemical Mechanisms |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cbic.202400106 |journal=ChemBioChem |language=en |volume=25 |issue=9 |pages=e202400106 |doi=10.1002/cbic.202400106 |issn=1439-7633|doi-access=free }} It is the substrate of firefly luciferase (EC 1.13.12.7), which is responsible for the characteristic light emission of many firefly and other insect species in the visible spectra ranging from 530 until 630 nm.{{Cite journal |last=Carrasco-López |first=César |last2=Lui |first2=Nathan M. |last3=Schramm |first3=Stefan |last4=Naumov |first4=Panče |date=2021 |title=The elusive relationship between structure and colour emission in beetle luciferases |url=https://www.nature.com/articles/s41570-020-00238-1 |journal=Nature Reviews Chemistry |language=en |volume=5 |issue=1 |pages=4–20 |doi=10.1038/s41570-020-00238-1 |issn=2397-3358|url-access=subscription }}
As with other luciferins, oxygen is essential for the luminescence mechanism, which involves the decomposition of a cyclic peroxide to produce excited-state molecules capable of emitting light as they relax to the ground state. Additionally, it has been found that adenosine triphosphate (ATP) and magnesium are required for light emission.{{cite journal | author = McElroy WD | title = The Energy Source for Bioluminescence in an Isolated System. | journal = Proc Natl Acad Sci USA | volume = 33 | pages = 342–345 | year = 1947 | pmid = 16588763 | doi = 10.1073/pnas.33.11.342 | issue = 11 | pmc = 1079070| bibcode = 1947PNAS...33..342M | doi-access = free }}{{cite journal |vauthors=Green A, McElroy WD | title = Function of adenosine triphosphate in the activation of luciferin. | journal = Arch Biochem Biophys | volume = 64 | pages = 257–271 | year = 1956 | pmid = 13363432 | doi = 10.1016/0003-9861(56)90268-5 | issue = 2 }}
History
Much of the early work on the chemistry of the firefly luminescence was done in the lab of William D. McElroy at Johns Hopkins University. The luciferin was first isolated and purified in 1949 from a large amount of specimens, though it would be several years until a procedure was developed to crystallize the compound in high yield.
This, along with the synthesis and structure elucidation, was accomplished by Dr. Emil H. White at the Johns Hopkins University, Department of Chemistry.{{cite journal |vauthors=Strehler BL, McElroy WD | title = Purification of firefly luciferin. | journal = J Cell Physiol | volume = 34 | pages = 457–466 | year = 1949 | pmid = 15406363 | doi = 10.1002/jcp.1030340310 | issue = 3 }} The procedure was an acid-base extraction, given the carboxylic acid group on the luciferin. The luciferin could be effectively extracted using ethyl acetate at low pH from powder of approximately 15,000 firefly lanterns.{{cite journal |vauthors=Bitler B, McElroy WD | title = The Preparation and Properties of Crystalline Firely Luciferin | journal = Arch Biochem Biophys | volume = 72 | pages = 358–368 | year = 1957 | pmid = 13479120 | doi = 10.1016/0003-9861(57)90212-6 | issue = 2}} The structure was later confirmed by combined use of infrared spectroscopy, UV–vis spectroscopy and synthetic methods to degrade the compound into identifiable fragments.{{cite journal |vauthors=White EH, McCapra F, Field GF, McElroy WD | title = The Structure and Synthesis of Firefly Luciferin | journal = J Am Chem Soc | volume = 83 | issue = 10 | pages = 2402–2403 | year = 1961 | doi = 10.1021/ja01471a051}}
Properties
Crystal luciferin was found to be fluorescent, absorbing ultraviolet light with a peak at 327 nm and emitting light with a peak at 530 nm. Visible emission occurs upon relaxation of the oxyluciferin from a singlet excited state down to its ground state.{{Cite journal|title=Firefly Bioluminescence: A Mechanistic Approach of Luciferase Catalyzed Reactions|journal=IUBMB Life|volume=61|issue=1|doi=10.1002/iub.134|pmid=18949818|year=2009|pages=6–17|vauthors=Marques SM, Joaquim|s2cid=21583225|doi-access=free}} Alkaline solutions caused a redshift of the absorption likely due to deprotonation of the hydroxyl group on the benzothiazole, but did not affect the fluorescence emission. It was found that the luciferyl adenylate (the AMP ester of luciferin) spontaneously emits light in solution.{{cite journal |vauthors=Rhodes WC, McElroy WD | title = The synthesis and function of luciferyl-adenylate and oxyluciferyl-adenylate. | journal = J Biol Chem | volume = 233 | pages = 1528–1537 | year = 1958 | pmid = 13610868 | issue = 6| doi = 10.1016/S0021-9258(18)49367-2 | doi-access = free }}
Different species of fireflies all use the same luciferin, however the color of the light emitted can differ greatly. The light from Photuris pennsylvanica was measured to be 552 nm (green-yellow) while Pyrophorus plagiophthalamus was measured to emit light at 582 nm (orange) in the ventral organ. Such differences are likely due to pH changes or differences in primary structure of the luciferase.{{cite journal |vauthors=Seliger HH, Buck JB, Fastie WG, McElroy WD | title = The Spectral Distribution of Firefly Light. | journal = J Gen Physiol | volume = 48 | issue = 1 | pages = 95–104 | year = 1964 | pmid = 14212153 | doi = 10.1085/jgp.48.1.95 | pmc = 2195396}} Modification of the firefly luciferin substrate has led to "red-shifted" emissions (up to emission wavelength of 675 nm).{{Cite journal|title=Multicolor Bioluminescence Obtained Using Firefly Luciferin|journal=Current Topics in Medicinal Chemistry|volume=16|issue=24|doi=10.2174/1568026616666160413135055|pmid=27072707|year=2016|pages=2648–2655|vauthors=Kiyama M, Saito R, Iwano S, Obata R, Niwa H, Maki SA}}
Biological activity
The in vivo synthesis of firefly luciferin is not completely understood. Only the final step of the enzymatic pathway has been studied, which is the condensation reaction of D-cysteine with 2-cyano-6-hydroxybenzothiazole, and is the same reaction used to produce the compound synthetically.{{cite journal |vauthors=White EH, Worther H, Field GF, McElroy WD | title = Analogs of Firefly Luciferin. | journal = J. Org. Chem. | volume = 30 | issue = 7 | pages = 2344–2348 | year = 1965 | doi = 10.1021/jo01018a054}} This was confirmed by radiolabeling of atoms in the two compounds and by identification of a luciferin-regenerating enzyme.{{cite journal |vauthors=Gomi K, Kajiyama N | title = Oxyluciferin, a Luminescence Product of Firefly Luciferase, Is Enzymatically Regenerated into Luciferin. | journal = J Biol Chem | volume = 276 | pages = 36508–36513 | year = 2001 | pmid = 11457857 | doi = 10.1074/jbc.M105528200 | issue = 39| doi-access = free }}
In firefly, oxidation of luciferins, which is catalyzed by luciferases, yields a peroxy compound 1,2-dioxetanone. The dioxetanone is unstable and via the release of carbon dioxide and excited ketones, which release excess energy by emitting light (bioluminescence).Aldo Roda [https://books.google.com/books?id=Gq_QDcADZxEC&pg=PA57 Chemiluminescence and Bioluminescence: Past, Present and Future], p. 57, Royal Society of Chemistry, 2010, {{ISBN|1-84755-812-7}}
File:Luciferin principle.pngFirefly luciferin and modified substrates are fatty acid mimics and have been used to localize fatty acid amide hydrolase (FAAH) in vivo.{{Cite journal|title=Luciferin Amides Enable in Vivo Bioluminescence Detection of Endogenous Fatty Acid Amide Hydrolase Activity|journal=J. Am. Chem. Soc.|volume=137|issue=27|doi=10.1021/jacs.5b04357|pmid=26120870|pmc=4507478|year=2015|pages=8684–8687|vauthors=Mofford DM, Adams ST, Kumar Reddy GS, Randheer Reddy G, Miller SC}} Firefly luciferin is a substrate of the ABCG2 transporter and has been used as part of a bioluminescence imaging high throughput assay to screen for inhibitors of the transporter.{{Cite journal|title=Identification of Inhibitors of ABCG2 by a Bioluminescence Imaging-Based High-Throughput Assay.|journal=Cancer Res.|volume=69}}{{clear}}
References
{{reflist|30em}}
External links
- [https://www.lifesci.ucsb.edu/~biolum/chem/detail1.html Bioluminescence Page] showing major luciferin types