Vargulin

Vargulin

Names
IUPAC name 2-[3-[2-[(2S)-butan-2-yl]-6-(1H-indol-3-yl)-3-oxo-7H-imidazo[2, 1-c]pyrazin-8-yl]propyl]guanidine
Other names Vargulin, Cypridina luciferin, cypridinluciferin
Identifiers
CAS Number	7273-34-9
ChemSpider	388868
Jmol 3D image	Interactive graph
PubChem	2762720
InChI InChI=1S/C22H27N7O/c1-3-13(2)19-21(30)29-12-18(15-11-26-16-8-5-4-7-14(15)16)27-17(20(29)28-19)9-6-10-25-22(23)24/h4-5,7-8,11-13,26-27H,3,6,9-10H2,1-2H3,(H4,23,24,25) Key: ZWPWSXGBDMGKKS-UHFFFAOYSA-N InChI=1S/C22H27N7O/c1-3-13(2)19-21(30)29-12-18(15-11-26-16-8-5-4-7-14(15)16)27-17(20(29)28-19)9-6-10-25-22(23)24/h4-5,7-8,11-13,26-27H,3,6,9-10H2,1-2H3,(H4,23,24,25)/t13-/m0/s1 Key: ZWPWSXGBDMGKKS-UHFFFAOYAG
SMILES O=C\3N4\C=C(\c2c1ccccc1nc2)N/C(=C4/N=C/3[C@@H](C)CC)CCC/N=C(\N)N
Properties
Chemical formula	C22H27N7O
Molar mass	405.496
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Vargulin, also called Cypridina luciferin or Vargula Luciferin, is the luciferin found in the ostracod Cypridina hilgendorfii, also named Vargula hilgendorfii.^[1] These bottom dwelling ostracods emit a light stream into water when disturbed presumably to deter predation. Vargulin is also used by the midshipman fish, Porichthys.

History

A partial extraction procedure was developed in 1935 which involved reacting the compound with benzoyl chloride to allow it to be separated from the water-soluble components.^[2] The compound was first isolated and purified to crystals by Osamu Shimomura.^[3] The structure of the compound was confirmed some years later.^[4] Feeding experiments suggest that the compound is synthesized in the animal from three amino-acids: tryptophan, isoleucine, and arginine.^[5]

Biochemistry

Vargulin is oxidized by the Vargula luciferase,^[6] a 62kDa enzyme, to produce blue light at 462 nm (max emission, detected with a 425 to 525 nm filter). The vargulin does not cross react with luciferases using Coelenterazine or Firefly luciferin.

Uses

Vargulin (with the associated luciferase) has applications in Biotechnology:

• in a variety of assays, to report gene or gene expression after luciferase have been genetically introduced in cells,
• to detect ATP, that is used in the vargulin/luciferase reaction (cell viability assays)

Although less stable, the Cypridina system is useful because can be used in multiplex assays with other (red-emitting) luciferin assays.

References

1. Shimomura, O. (2006). Bioluminescence: Chemical Principles and Methods. World Scientific Publishing. ISBN 978-981-256-801-4.
2. Anderson, RS (1935). "Studies on Bioluminescence : II. the Partial Purification of Cypridina Luciferin.". The Journal of General Physiology 19 (2): 301–5. doi:10.1085/jgp.19.2.301. PMID 19872927.
3. Shimomura, O, Goto, T, and Hirata, Y (1957). "Crystalline Cypridina Luciferin". Bulletin of the Chemical Society of Japan 30 (8): 929–933. doi:10.1246/bcsj.30.929.
4. Kishi Y, Goto, T, Hirata Y, Shiromura O and Johnson FH (1966). "Cypridina bioluminescence. I. Structure of Cypridina luciferin". Tetrahedron Lett. 7: 3427–3436. doi:10.1016/S0040-4039(01)82806-9.
5. Oba, Y, Kato, S, Ojika, M and Inouye, S (2002). "Biosynthesis of luciferin in the sea firefly, Cypridina hilgendorfii: l-tryptophan is a component in Cypridina luciferin". Tetrahedron Letters 43 (12): 2389–2392. doi:10.1016/S0040-4039(02)00257-5.
6. Thompson EM, Nagata S, Tsuji FI (1989). "Cloning and expression of cDNA for the luciferase from the marine ostracod Vargula hilgendorfii". Proceedings of the National Academy of Sciences 86 (17): 6567–71. doi:10.1073/pnas.86.17.6567. PMC 297885. PMID 2771943.