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Discharged photoprotein obelin: Fluorescence peculiarities

Paper ID Volume ID Publish Year Pages File Format Full-Text
30971 44522 2010 6 PDF Available
Title
Discharged photoprotein obelin: Fluorescence peculiarities
Abstract

Photoprotein obelin, the enzyme–substrate complex of polypeptide with 2-hydroperoxycoelenterazine, is responsible for bioluminescence of marine hydroid Obelia longissima. Addition of Ca2+ to the photoprotein triggers the bioluminescent reaction with light emission. The product of the bioluminescent reaction – enzyme-bound coelenteramide – is a fluorescent protein called ‘discharged’ obelin. It is stable and highly fluorescent. The paper considers dependence of its light-induced fluorescence on Ca2+ concentration. Increase of Ca2+ concentration enhanced the fluorescence intensity of discharged obelin; the dependence was found as linear in double logarithmic coordinates at Ca2+ concentration range 10−7–10−6 М, both in excitation and emission spectra. The spectra were divided into components; contributions of the components to experimental excitation and emission spectra depended on Ca2+ concentration. The data suggest enzymatic conformational transition in discharged obelin at ∼5 × 10−7 M of Ca2+ concentration. Spectra variations were attributed to acidity changes of discharged obelin chromophore (coelenteramide) in its fluorescent state S1∗.

Keywords
Fluorescent protein; Discharged photoprotein; Obelin; Spectral components; Calcium; Conformational transition
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 101, Issue 1, 5 October 2010, Pages 103–108
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
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Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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Any Questions? feel free to contact us