Additive Effects of Chlorin E6 and Metal Ion Binding on the Thermal Stability of Rhodopsin In Vitro
Additive Effects of Chlorin E6 and Metal Ion Binding on the Thermal Stability of Rhodopsin In Vitro
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DOI：
10.1111/j.1751-1097.2009.00539.x
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发表时间：
2009-03-01
影响因子：
3.3
通讯作者：
Klein-Seetharaman, Judith
中科院分区：
文献类型：
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作者：
Balem, Fernanda;Yanamala, Naveena;Klein-Seetharaman, Judith
锌（Zn2+）缺乏会导致视网膜功能障碍，如夜盲症和神经变性。由于Zn2+直接与视紫红质结合并改变其稳定性，因此视紫红质的稳定可能是预防和治疗视网膜功能障碍的关键。本文研究了微量金属和其他营养物质是否能在体外稳定视紫红质结构。利用圆二色性和荧光光谱技术详细研究了叶绿素衍生物氯e6单独存在和不存在以及与二价金属离子Zn2+、Cu2+、Fe2+、Ni2+、Mg2+和Mn2+在5-100℃温度范围内的二级和三级结构的热稳定性。当同时存在氯e6和Zn2+时，与单独存在任何一种化合物相比，观察到总体二级结构含量的热稳定性显著增加。Cu2+也有这种添加能力，但其他金属离子和氯e6结合时则没有。
Zinc (Zn2+) deficiency causes retinal dysfunctions such as night blindness and neurodegeneration. Because Zn2+ binds directly to the photoreceptor rhodopsin and alters its stability, the stabilization of rhodopsin may be key to prevention and treatment of retinal dysfunctions. In this paper, we investigated if not only trace metals but also other nutrients may stabilize rhodopsin structure in vitro. Detailed studies of the thermal stability of secondary and tertiary structure of rhodopsin in the presence and absence of the chlorophyll derivative chlorin e6 alone and together with bivalent metal ions Zn2+, Cu2+, Fe2+, Ni2+, Mg2+ and Mn2+ over a temperature range 5-100 degrees C were conducted using circular dichroism and fluorescence spectroscopy. When both chlorin e6 and Zn2+ are present, a pronounced increase in the thermal stability of overall secondary structure content is observed compared to either compound alone. This additive capacity is also noted with Cu2+, but not when other metal ions and chlorin e6 are combined.