Oxygen Activation of Apo-obelin-Coelenterazine Complex
Oxygen Activation of Apo-obelin-Coelenterazine Complex
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DOI：
10.1002/cbic.201300002
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发表时间：
2013-04-15
期刊：
影响因子：
3.2
通讯作者：
Vysotski, Eugene S.
中科院分区：
文献类型：
--
作者：
Eremeeva, Elena V.;Natashin, Pavel V.;Vysotski, Eugene S.
Ca 2+调节的发光蛋白使用非共价结合的2-氢过氧腔肠素配体响应于Ca 2+结合而发光。为了更好地了解从载脂蛋白，腔肠素和分子氧的活性发光蛋白的形成机制，我们研究了厌氧的apo-obelincoelentreazine复合物的光谱特性和暴露于空气后其转化为活性发光蛋白的动力学。我们的研究表明，腔肠素结合在厌氧复合物可能是一个混合物的N7-质子化和C2（）阴离子的形式，和氧移动的平衡有利于C2（）阴离子作为过氧阴离子形成的结果。从N7质子去除和进一步质子化的过氧阴离子和由此产生的形成2-hydroperoxidecoelenterrazine在obelin可能会发生与His 175的援助。有人提出，这个保守的His残基可能发挥关键作用，在形成活性光蛋白和Ca 2+触发的生物发光反应。
Ca2+-regulated photoproteins use a noncovalently bound 2-hydroperoxycoelenterazine ligand to emit light in response to Ca2+ binding. To better understand the mechanism of formation of active photoprotein from apoprotein, coelenterazine and molecular oxygen, we investigated the spectral properties of the anaerobic apo-obelincoelenterazine complex and the kinetics of its conversion into active photoprotein after exposure to air. Our studies suggest that coelenterazine bound within the anaerobic complex might be a mixture of N7-protonated and C2() anionic forms, and that oxygen shifts the equilibrium in favor of the C2() anion as a result of peroxy anion formation. Proton removal from N7 and further protonation of peroxy anion and the resulting formation of 2-hydroperoxycoelenterazine in obelin might occur with the assistance of His175. It is proposed that this conserved His residue might play a key role both in formation of active photoprotein and in Ca2+-triggering of the bioluminescence reaction.