Structural highlights
Function[OBL_OBELO] Ca(2+)-dependent bioluminescence photoprotein. Displays an emission peak at 470 nm (blue light). Trace amounts of calcium ion trigger the intramolecular oxidation of the chromophore, coelenterazine into coelenteramide and CO(2) with the concomitant emission of light. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe spatial structure of the Ca(2+)-regulated photoprotein obelin has been solved to resolution of 1.1A. Two oxygen atoms are revealed substituted at the C2-position of the coelenterazine in contrast to the obelin structure at 1.73A resolution where one oxygen atom only was disclosed. The electron density of the second oxygen atom was very weak but after exposing the crystals to a trace of Ca(2+), the electron densities of both oxygen atoms became equally intense. In addition, one Ca(2+) was found bound in the loop of the first EF-hand motif. Four of the ligands were provided by protein residues Asp30, Asn32, Asn34, and the main chain oxygen of Lys36. The other two were from water molecules. From a comparison of B-factors for the residues constituting the active site, it is suggested that the variable electron densities observed in various photoprotein structures could be attributed to different mobilities of the peroxy oxygen atoms. Atomic resolution structure of obelin: soaking with calcium enhances electron density of the second oxygen atom substituted at the C2-position of coelenterazine.,Liu ZJ, Vysotski ES, Deng L, Lee J, Rose J, Wang BC Biochem Biophys Res Commun. 2003 Nov 14;311(2):433-9. PMID:14592432[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||||||
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