Optical Properties of Isolated Hormone Oxytocin Dianions: Ionization, Reduction, and Copper Complexation Effects
Optical Properties of Isolated Hormone Oxytocin Dianions: Ionization, Reduction, and Copper Complexation Effects
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DOI：
10.1021/jp810342s
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发表时间：
2009-06-18
影响因子：
2.9
通讯作者：
Dugourd, Philippe
中科院分区：
文献类型：
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作者：
Joly, Laure;Antoine, Rodolphe;Dugourd, Philippe
被捕获的催产素（OT）肽二价阴离子和铜-催产素复合物二价阴离子在受到紫外线照射时会发生电子脱离。对天然含二硫化物的环催产素、还原的二硫醇催产素和 Cu-II-催产素复合物进行了作为激光波长函数的电子光脱离实验。电子脱离率用于监测捕获离子的激发电子能谱。该光谱可用作不同结构环境下酪氨酸发色团电离态的指纹。在气相催产素二阴离子[OT-2H](2-) 中，酪氨酸被去质子化，而对于还原形式的催产素[OTSH-2H](2-) 呈中性。铜络合物二阴离子[OT-4H+Cu](2-)的光谱有利于络合物中的中性酪氨酸。对于该配合物，提出了一种金属阳离子螯合到四个去质子化酰胺基团的结构。
Trapped oxytocin (OT) peptide dianions and copper-oxytocin complex dianions are subjected to electron detachment when irradiated by a UV light. Electron photodetachment experiments as a function of the laser wavelength were performed on the native disulfide-containing ring oxytocin, the reduced dithiol oxytocin, and the Cu-II-oxytocin complex. The electron detachment yield was used to monitor the excited electronic spectrum of the trapped ions. The spectra can be used as a fingerprint of the ionization state of the tyrosine chromophore under different structural environments. In gas-phase oxytocin dianion [OT-2H](2-), the tyrosine is deprotonated while it is neutral for the reduced form of oxytocin [OTSH-2H](2-). Optical spectra for the copper complex dianion [OT-4H+Cu](2-) are in favor of a neutral tyrosine in the complex. A structure with the metal cation chelated to four deprotonated amide groups is proposed for this complex.