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Information on EC 1.13.12.24 - calcium-regulated photoprotein

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IUBMB Comments
Ca2+-regulated photoproteins are found in a variety of bioluminescent marine organisms, mostly coelenterates, and are responsible for their light emission. The best studied enzyme is from the jellyfish Aequorea victoria. The enzyme tightly binds the imidazolopyrazinone derivative coelenterazine, which is then peroxidized by oxygen. The hydroperoxide is stably bound until three Ca2+ ions bind to the protein, inducing a structural change that results in the formation of a 1,2-dioxetan-3-one ring, followed by decarboxylation and generation of a protein-bound coelenteramide in an excited state. The calcium-bound protein-product complex is known as a blue fluorescent protein. In vivo the energy is transferred to a green fluorescent protein (GFP) by Forster resonance energy transfer. In vitro, in the absence of GFP, coelenteramide emits a photon of blue light while returning to its ground state.
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UNIPROT: Q27709
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The expected taxonomic range for this enzyme is: Eumetazoa
Reaction Schemes
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[apoaequorin]
+
coelenterazine
+
O2
+
3
Ca2+
=
[excited state blue fluorescent protein]
+
CO2
[apoaequorin]
+
+
+
3
=
[excited state blue fluorescent protein]
+
Synonyms
obelin, blue fluorescent protein, mnemiopsin, berovin, mitrocomin, mnemiopsin 2, ca2+-regulated photoprotein, calcium-regulated photoprotein, halistaurin, phialidin, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
aequorin
-
-
-
-
alcium-activated photoprotein
-
-
-
-
berovin
-
-
-
-
Ca2+-regulated photoprotein
-
-
-
-
clytin
-
-
-
-
halistaurin
-
-
-
-
mitrocomin
-
-
-
-
mnemiopsin
-
-
-
-
obelin
-
-
-
-
phialidin
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
coelenterazine:oxygen 2-oxidoreductase (decarboxylating, calcium-dependent)
Ca2+-regulated photoproteins are found in a variety of bioluminescent marine organisms, mostly coelenterates, and are responsible for their light emission. The best studied enzyme is from the jellyfish Aequorea victoria. The enzyme tightly binds the imidazolopyrazinone derivative coelenterazine, which is then peroxidized by oxygen. The hydroperoxide is stably bound until three Ca2+ ions bind to the protein, inducing a structural change that results in the formation of a 1,2-dioxetan-3-one ring, followed by decarboxylation and generation of a protein-bound coelenteramide in an excited state. The calcium-bound protein-product complex is known as a blue fluorescent protein. In vivo the energy is transferred to a green fluorescent protein (GFP) by Forster resonance energy transfer. In vitro, in the absence of GFP, coelenteramide emits a photon of blue light while returning to its ground state.
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
[apoaequorin] + coelenterazine + O2 + 3 Ca2+
[excited state blue fluorescent protein] + CO2
show the reaction diagram
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
[apoaequorin] + coelenterazine + O2 + 3 Ca2+
[excited state blue fluorescent protein] + CO2
show the reaction diagram
-
-
-
?
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Ca2+
Ca2+-regulated photoprotein
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
OBL_OBELO
195
0
22226
Swiss-Prot
-
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
to 1.7 A resolution. A calcium ion is observed in each of the three EF-hand loops that have the canonical calcium-binding sequence, and each is coordinated in the characteristic pentagonal bipyramidal configuration. The calcium-loaded apo-protein retains the same compact scaffold and overall fold as the unreacted photoprotein containing the bound substrate, 2-hydroperoxycoelenterazine and also the same as the Ca2+-discharged obelin bound with the product, coelenteramide
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
F88H
mutation shifts the bioluminescence maximum from 482 nm for wild-type to 459 nm. 105% of wild-type bioluminescence yield
F88R
mutation shifts the bioluminescence maximum from 482 nm for wild-type to 474 nm. 99% of wild-type bioluminescence yield
F88W
mutation shifts the bioluminescence maximum from 482 nm for wild-type to 477 nm. 100% of wild-type bioluminescence yield
F88Y
mutation shifts the bioluminescence maximum from 482 nm for wild-type to 453 nm. 100% of wild-type bioluminescence yield
additional information
mutation of all 5 Cys resiudes to Ser. Cys-free obelin retains only about 10% of the bioluminescence activity of wild-type obelin and binds coelenterazine and forms active photoprotein much less effectively. The mutation drastically changes the bioluminescence kinetics of obelin completely eliminating a fast component from the light signal decay curve. Replacement of Cys residues increases conformational flexibility
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
28.8
Cys-free mutant, melting temperature
49.1
wild-type, melting temperature
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
expression in Escherichia coli BL21
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
analysis
use of the enzyme as an instrument to monitor the development of high specific DNA aptamers
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Stepanyuk, G.A.; Golz, S.; Markova, S.V.; Frank, L.A.; Lee, J.; Vysotski, E.S.
Interchange of aequorin and obelin bioluminescence color is determined by substitution of one active site residue of each photoprotein
FEBS Lett.
579
1008-1014
2005
Aequorea victoria (P02592), Obelia longissima (Q27709)
Manually annotated by BRENDA team
Eremeeva, E.; Vysotski, E.
Bioluminescent and biochemical properties of Cys-free Ca2+-regulated photoproteins obelin and aequorin
J. Photochem. Photobiol. B
174
97-105
2017
Aequorea victoria (P07164), Obelia longissima (Q27709)
Manually annotated by BRENDA team
Deng, L.; Vysotski, E.S.; Markova, S.V.; Liu, Z.J.; Lee, J.; Rose, J.; Wang, B.C.
All three Ca2+-binding loops of photoproteins bind calcium ions the crystal structures of calcium-loaded apo-aequorin and apo-obelin
Protein Sci.
14
663-675
2005
Aequorea victoria (P02592), Obelia longissima (Q27709)
Manually annotated by BRENDA team
Krasitskaya, V.V.; Goncharova, N.S.; Biriukov, V.V.; Bashmakova, E.E.; Kabilov, M.R.; Baykov, I.K.; Sokolov, A.E.; Frank, L.A.
The Ca2+-regulated photoprotein obelin as a tool for SELEX monitoring and DNA aptamer affinity evaluation
Photochem. Photobiol.
96
1041-1046
2020
Obelia longissima (Q27709)
Manually annotated by BRENDA team
Malikova, N.P.; Eremeeva, E.V.; Gulnov, D.V.; Natashin, P.V.; Nemtseva, E.V.; Vysotski, E.S.
Specific activities of hydromedusan Ca2+-regulated photoproteins
Photochem. Photobiol.
98
275-283
2022
Aequorea victoria (P07164), Mitrocoma cellularia (P39047), Clytia gregaria (Q08121), Obelia longissima (Q27709), Obelia geniculata (Q8T6Z0)
Manually annotated by BRENDA team