Obelia longissima

Bondar, V. S., Vysotskii, E. S., Gamalei, I. A., and Kaulin, A. B. (1991). Isolation, properties, and application of calcium activated photoprotein from the hydroid polyp Obelia longissima. Tsitologiya 33 50-59. 

Gitelzon, G. I., Tugai, V. A., and Zakharchenko, A. N. (1990). Production of obelin, a calcium-activated photoprotein, from Obelia longissima and its application for registration of the calcium efflux from the fragmented sarcoplasmic reticulum of skeletal muscles. Ukr. Biokhim. Zh. 62 69-76. 

Illarionov, B. A., et al. (1992). Cloning and expression of cDNA coding for the calcium-activated photoprotein obelin from the hydroid polyp Obelia longissima. Dokl. Akad. Nauk SSSR 326 911-913. 

Letunov, V. N., and Vysotski, E. S. (1988). Bioluminescence activity and content of calcium-dependent photoprotein in Obelia longissima (Pallas) hydroid colonies. Zh. Obshch. Biol. 49 381-387. 

Vysotski, E. S., etal. (1999). Preparation and preliminary study of crystals of the recombinant calcium-regulated photoprotein obelin from the biolu-minescent hydroid Obelia longissima. Acta Cryst. D55 1965-1966. 

Obelin is a Ca2+-activated bioluminescent photoprotein that has been isolated from the marine polyp Obelia longissima. Binding of calcium ions determines a luminescent emission. The protein consists of 195 amino acid residues [264] and is composed of apoobelin, coelenterazine, and oxygen. As aequorin, it contains three EF-hand Ca2+-binding sites and the luminescent reaction may be the result of coelenterazine oxidation by way of an intramolecular reaction that produces coelenteramide, C02, and blue light. As for aequorin, the luminescent reaction of obelin is sensitive to calcium and the protein was used in the past as an intracellular Ca2+ indicator. More recently, the cloning of cDNA for apoobelin led to the use of recombinant obelin as a label in different analytical systems. 

Bioluminescent enzymes bacterial luciferase from Photobacterium leiognathi and apo-obelin from the marine hydroid polyp Obelia longissima were purchased from the Photobiology Laboratory (Institute of Biophysics, SB RAS, Krasnoyarsk, Russia). Anthracene derivatives (2-chloranthracene (CA), 9-bromanthracene (BA)... 

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