This article is missing information about more other proteins that catalyze this reaction (EC, sigh).(November 2020) |
Renilla-luciferin 2-monooxygenase | |||||||||
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Identifiers | |||||||||
EC no. | 1.13.12.5 | ||||||||
CAS no. | 61869-41-8 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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Renilla-luciferin 2-monooxygenase, Renilla luciferase, or RLuc, is a bioluminescent enzyme found in Renilla reniformis , belonging to a group of coelenterazine luciferases. Of this group of enzymes, the luciferase from Renilla reniformis has been the most extensively studied, and due to its bioluminescence requiring only molecular oxygen, has a wide range of applications, with uses as a reporter gene probe in cell culture, in vivo imaging, and various other areas of biological research. [2] Recently, chimeras of RLuc have been developed and demonstrated to be the brightest luminescent proteins to date, and have proved effective in both noninvasive single-cell and whole body imaging. [3]
Note that the EC record also includes other unrelated enzymes that catalyze the same reaction. An example is the calcium-dependent photoprotein aequorin: while Rluc is in the AB hydrolase superfamily, aequorin is an EF hand protein. [4] The name does not specifically refer to Renilla, but instead refers to Renilla-luciferin, a chemical also known as coelenterazine.
RLuc is an oxidoreductase, specifically acting on single donors with O2 as the oxidant. However, this enzyme appears to be unrelated from most other luciferases that act on coelenterazine, such as those from copepods. RLuc catalyzes the chemical reaction
Coelenterazine + O2 coelenteramide + CO2 + hν
In the process, coelenterazine is oxidized with a concurrent loss of CO2, and a photon of blue light is emitted. [5]
In Renilla reniformis, RLuc is found in membrane-bound intracellular structures within specialized light emitting cells, [6] [7] and is coupled with a closely interacting green fluorescent protein (RrGFP), [8] and a Ca++ activated luciferin binding protein (RrLBP). [9] Although the luciferase catalyzed oxidation of coelenterazine releases a photon of blue light (480 nm), this is not observed in vivo. Instead, the energy released by the reaction involving RLuc is passed via resonance energy transfer to the fluorophore of RrGFP and emitted as a green photon (505 nm), [10] resulting in green bioluminescence observed from the animal. This process relies on a Förster resonance energy transfer (FRET) mechanism, increasing the emitted photon number approximately six-fold. [11]
Renilla luciferase contains 311 amino acids, [1] and is active as a nearly spherical single polypeptide chain monomer of 36 kDa, which have a tendency for self-association, forming inactive dimers and trimers. [12] [13] Like other dehalogenase-superfamily enzymes, it has a characteristic α/β-hydrolase fold sequence at its core [14] and shares the conserved catalytic triad of residues employed by dehalogenases. [15] In RLuc, the loop containing residues 153 – 163 is structurally flexible, facilitating greater diffusion of solvents into the active site, which contains a highly-conserved catalytic triad consisting of Aspartic Acid at residue 120, Glutamic Acid at residue 144, and Histidine at residue 285. [1]
Unlike photoproteins which stably bind coelenterazine and emit light upon addition of calcium, coelenterazine is normally bound by RrLBP, the luciferin-binding protein. When stimulated, a Ca2+ ion first interacts with RrLBP, causing it to release coelenterazine. [9] Coelenterazine is then oxidized by RLuc into coelenteramide, releasing a single photon of blue light (480 nm) in the process. This photon is captured by the adjacent GFP, releasing a photon of green light. This pathway is summarized below.
The RLuc mediated chemical reaction involves the catalytic degradation of coelenterazine, and proceeds through a 1,2-dioxetane (also called dioxetanone or cyclic peroxide) intermediate. [16] Based on studies using radioactively labelled oxygen species within the RLuc complex, it has been determined that the luciferin carbonyl oxygen is exchanged rapidly with oxygen from water prior to incorporation of an oxygen atom from O2 via a dioxetane intermediate. The resultant CO2 also rapidly exchanges its oxygens with those from the surrounding water. [17] The general mechanism is depicted below.
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, and terrestrial arthropods such as fireflies. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves.
Chemiluminescence is the emission of light (luminescence) as the result of a chemical reaction, i.e. a chemical reaction results in a flash or glow of light. A standard example of chemiluminescence in the laboratory setting is the luminol test. Here, blood is indicated by luminescence upon contact with iron in hemoglobin. When chemiluminescence takes place in living organisms, the phenomenon is called bioluminescence. A light stick emits light by chemiluminescence.
Luciferase is a generic term for the class of oxidative enzymes that produce bioluminescence, and is usually distinguished from a photoprotein. The name was first used by Raphaël Dubois who invented the words luciferin and luciferase, for the substrate and enzyme, respectively. Both words are derived from the Latin word lucifer, meaning "lightbearer", which in turn is derived from the Latin words for "light" (lux) and "to bring or carry" (ferre).
Luciferin is a generic term for the light-emitting compound found in organisms that generate bioluminescence. Luciferins typically undergo an enzyme-catalyzed reaction with molecular oxygen. The resulting transformation, which usually involves breaking off a molecular fragment, produces an excited state intermediate that emits light upon decaying to its ground state. The term may refer to molecules that are substrates for both luciferases and photoproteins.
Aequorin is a calcium-activated photoprotein isolated from the hydrozoan Aequorea victoria. Its bioluminescence was studied decades before the protein was isolated from the animal by Osamu Shimomura in 1962. In the animal, the protein occurs together with the green fluorescent protein to produce green light by resonant energy transfer, while aequorin by itself generates blue light.
Firefly luciferase is the light-emitting enzyme responsible for the bioluminescence of fireflies and click beetles. The enzyme catalyses the oxidation of firefly luciferin, requiring oxygen and ATP. Because of the requirement of ATP, firefly luciferases have been used extensively in biotechnology.
Firefly luciferin is the luciferin, or light-emitting compound, used for the firefly (Lampyridae), railroad worm (Phengodidae), starworm (Rhagophthalmidae), and click-beetle (Pyrophorini) bioluminescent systems. It is the substrate of luciferase, which is responsible for the characteristic yellow light emission from many firefly species.
Bioluminescence imaging (BLI) is a technology developed over the past decades (1990's and onward). that allows for the noninvasive study of ongoing biological processes Recently, bioluminescence tomography (BLT) has become possible and several systems have become commercially available. In 2011, PerkinElmer acquired one of the most popular lines of optical imaging systems with bioluminescence from Caliper Life Sciences.
A photocyte is a cell that specializes in catalyzing enzymes to produce light (bioluminescence). Photocytes typically occur in select layers of epithelial tissue, functioning singly or in a group, or as part of a larger apparatus. They contain special structures termed as photocyte granules. These specialized cells are found in a range of multicellular animals including ctenophora, coelenterates (cnidaria), annelids, arthropoda and fishes. Although some fungi are bioluminescent, they do not have such specialized cells.
In enzymology, a Latia-luciferin monooxygenase (demethylating) (EC 1.14.99.21) is an enzyme that catalyzes the chemical reaction
In enzymology, a Cypridina-luciferin 2-monooxygenase (EC 1.13.12.6) is an enzyme that catalyzes the chemical reaction
In enzymology, an Oplophorus-luciferin 2-monooxygenase, also known as Oplophorus luciferase is a luciferase, an enzyme, from the deep-sea shrimp Oplophorus gracilirostris [2], belonging to a group of coelenterazine luciferases. Unlike other luciferases, it has a broader substrate specificity [3,4,6] and can also bind to bisdeoxycoelenterazine efficiently [3,4]. It is the third example of a luciferase to be purified in lab [2]. The systematic name of this enzyme class is Oplophorus-luciferin:oxygen 2-oxidoreductase (decarboxylating). This enzyme is also called Oplophorus luciferase.
In enzymology, a Renilla-luciferin sulfotransferase is an enzyme that catalyzes the chemical reaction
Bioreporters are intact, living microbial cells that have been genetically engineered to produce a measurable signal in response to a specific chemical or physical agent in their environment. Bioreporters contain two essential genetic elements, a promoter gene and a reporter gene. The promoter gene is turned on (transcribed) when the target agent is present in the cell’s environment. The promoter gene in a normal bacterial cell is linked to other genes that are then likewise transcribed and then translated into proteins that help the cell in either combating or adapting to the agent to which it has been exposed. In the case of a bioreporter, these genes, or portions thereof, have been removed and replaced with a reporter gene. As a result, turning on the promoter gene also turns on the reporter gene, leading to the production of reporter proteins that output a detectable signal. The presence of a signal indicates that the bioreporter has sensed a particular agent in its environment.
Coelenterazine is a luciferin, a molecule that emits light after reaction with oxygen, found in many aquatic organisms across eight phyla. It is the substrate of many luciferases such as Renilla reniformis luciferase (Rluc), Gaussia luciferase (Gluc), and photoproteins, including aequorin, and obelin. All these proteins catalyze the oxidation of this substance, a reaction catalogued EC 1.13.12.5.
Photoproteins are a type of enzyme produced by bioluminescent organisms. They add to the function of the luciferins whose usual light-producing reaction is catalyzed by the enzyme luciferase.
John Woodland "Woody" Hastings, was a leader in the field of photobiology, especially bioluminescence, and was one of the founders of the field of circadian biology. He was the Paul C. Mangelsdorf Professor of Natural Sciences and Professor of Molecular and Cellular Biology at Harvard University. He published over 400 papers and co-edited three books.
Dinoflagellate luciferase (EC 1.13.12.18, Gonyaulax luciferase) is a specific luciferase, an enzyme with systematic name dinoflagellate-luciferin:oxygen 132-oxidoreductase.
Bioluminescent bacteria are light-producing bacteria that are predominantly present in sea water, marine sediments, the surface of decomposing fish and in the gut of marine animals. While not as common, bacterial bioluminescence is also found in terrestrial and freshwater bacteria. These bacteria may be free living or in symbiosis with animals such as the Hawaiian Bobtail squid or terrestrial nematodes. The host organisms provide these bacteria a safe home and sufficient nutrition. In exchange, the hosts use the light produced by the bacteria for camouflage, prey and/or mate attraction. Bioluminescent bacteria have evolved symbiotic relationships with other organisms in which both participants benefit close to equally. Another possible reason bacteria use luminescence reaction is for quorum sensing, an ability to regulate gene expression in response to bacterial cell density.
Scintillons are small structures in cytoplasm that produce light. Among bioluminescent organisms, only dinoflagellates have scintillons.