Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/18 09:59:30」(JST)

wiki en

Photoproteins are a type of enzyme, made of protein, from bioluminescent organisms. They add to the function of the typical luciferin protein whose usual light-producing reaction is catalyzed by the enzyme luciferase.

History

The marine worm Chaetopterus was the source of the first photoprotein to be discovered.

The term photoprotein was first used to describe the unusual chemistry of the luminescent system of Chaetopterus (a marine Polychaete worm).^[1] This was meant to distinguish them from other light-producing proteins because these do not exhibit the usual luciferin-luciferase reaction.^[2]

Reaction kinetics

Photoproteins do not display typical enzyme kinetics as seen in luciferases. Instead, when mixed with luciferin, they display luminescence proportional to the amount of the photoprotein. For example, the photoprotein aequorin produces a flash of light when luciferin and calcium are added, rather than the prolonged glow that is seen for luciferases when luciferin is added. In this respect, it may appear that photoproteins are not enzymes, when in fact they do catalyze their bioluminescence reactions. This is due to a fast catalyic step, which produces the light, and a slow regeneration step, where the oxyluciferin is freed and another molecule of luciferin is then enabled to bind to the enzyme.^[3] Because of the kinetically slow step, each aequorin molecule must "recharge" with another molecule of luciferin before it can emit light again, and this makes it appear as though it is not behaving as a typical enzyme.

Photoproteins form a stable luciferin-photoprotein complex, often until the addition of another required factor such as Ca²⁺ in the case of aequorin.

References

^ Shimomura, O. "Bioluminescence: Chemical Principles and Methods" World Scientific Publishing Co., 2006.
^ Harvey, E.N. "Bioluminescence" Academic Press., 1952.
^ Shimomura O, Johnson FH (1975). "Regeneration of the photoprotein aequorin". Nature 256 (5514): 236–238. doi:10.1038/256236a0. PMID 239351.

English Journal

Codon optimization of genes for efficient protein expression in mammalian cells by selection of only preferred human codons.

Inouye S1, Sahara-Miura Y2, Sato J2, Suzuki T3.
Protein expression and purification.Protein Expr Purif.2015 May;109:47-54. doi: 10.1016/j.pep.2015.02.002. Epub 2015 Feb 7.
A simple design method for codon optimization of genes to express a heterologous protein in mammalian cells is described. Codon optimization was performed by choosing only codons preferentially used in humans and with over 60% GC content, and the method was named the "preferred human codon-optimized
PMID 25665506

Hyperactive Arg39Lys mutated mnemiopsin: implication of positively charged residue in chromophore binding cavity.

Mahdavi A1, Sajedi RH, Hosseinkhani S, Taghdir M.
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology.Photochem Photobiol Sci.2015 Apr 1;14(4):792-800. doi: 10.1039/c4pp00191e.
Mnemiopsin, a Ca(2+)-regulated photoprotein isolated from Mnemiopsis leidyi, belongs to the family of ctenophore photoproteins. These proteins emit blue light from a chromophore, which is tightly but non-covalently bound in their central hydrophobic core that contains 21 conserved residues. In an ef
PMID 25635518

Inhibition of Anopheles gambiae Odorant Receptor Function by Mosquito Repellents.

Tsitoura P1, Koussis K2, Iatrou K3.
The Journal of biological chemistry.J Biol Chem.2015 Mar 20;290(12):7961-72. doi: 10.1074/jbc.M114.632299. Epub 2015 Feb 5.
The identification of molecular targets of insect repellents has been a challenging task, with their effects on odorant receptors (ORs) remaining a debatable issue. Here, we describe a study on the effects of selected mosquito repellents, including the widely used repellent N,N-diethyl-meta-toluamid
PMID 25657000

Japanese Journal

ヒカリカモメガイ由来の発光タンパク質（フォラシン）:小さな発見に至るまでの長い道のり

久世雅樹
化学と生物 52(3), 166-171, 2014
ヒカリカモメガイの発光器には発光タンパク質（フォラシン）があり，活性酸素種 (ROS) の刺激により青色に発光する．フォラシンはROS検出キットとして市販されているにもかかわらず，発光に関与しているクロモフォア（発光を司る化学構造）の構造は不明であった．そのため，フォラシンの遺伝子発現はすでに達成されていたが，クロモフォアを構成することができず発光させることは不可能であった．筆者らはトビイカの発光 …
NAID 130004808960

Streptavidin-Aequorin Fusion Protein for Bioluminescent Immunoassay

Inouye Satoshi,Sato Jun-ichi,Sasaki Satoko [他],SAHARA Yuiko
Bioscience, biotechnology, and biochemistry 75(3), 568-571, 2011-03-23
The fusion protein of streptavidin to aequorin (STA-AQ) was highly purified from inclusion bodies in <I>Escherichia coli</I> cells and applied to a bioluminescent sandwich immunoassay. α-F …
NAID 10028202035

発光タンパク質による光イメージング

秋元秀俊,安東頼子,近江谷克裕
生物物理 49(2), 70-74, 2009-03-25
Imaging is an essential approach to understanding the physiological systems of organism. Luminescence imaging based on luciferase technology reveals biological phenomena from molecule to body by light …
NAID 10025975469