Sugar-induced blue membrane: release of divalent cations during phase transition of purple membranes observed in sugar-derived glasses.
Sugar-induced blue membrane: release of divalent cations during phase transition of purple membranes observed in sugar-derived glasses.
复制标题
糖诱导的蓝色膜：在糖衍生玻璃中观察到的紫色膜相变过程中二价阳离子的释放
DOI：
10.1021/jp710694s
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
N. Hampp
中科院分区：
文献类型：
--
作者：
D. Rhinow;N. Hampp
紫膜（PM）由紫膜（PM）形成蓝膜已在由PM和各种糖制成的玻璃膜中观察到。PM在70℃左右的相变使二价阳离子的络合作用减弱。只要糖的玻璃化转变温度低于PM的相变温度，糖中的邻二醇结构就能使二价阳离子络合并在整个基体中离域。细菌视紫红质（BR）是PM中唯一的蛋白质，其二价阳离子的丢失导致蓝膜（BM）的形成，并伴随着红外光谱中可观察到的β-片结构的丢失。玻璃糖对观察这种转变特别有用，因为糖的包裹并不限制BR的构象变化，而是延缓它们的变化。所得材料被命名为糖诱导蓝膜（SIBM）。二价阳离子的加入抑制了SIBM的形成。此外，通过加水，SIBM可以立即还原为PM。SIBM热还原到PM的特征时间依赖性证明PM的相变触发了二价阳离子的释放和摄取以及相应的颜色变化。
The formation of blue membrane from purple membranes (PM) has been observed in glassy films made from PM and various sugars. The phase transition of PM at about 70 °C causes the complexation of divalent cations to be weakened. The vicinal diol structures in sugars are capable to complex divalent cations and delocalize them throughout the matrix as long as its glass transition temperature is lower than the phase transition temperature of PM. The loss of divalent cations from bacteriorhodopsin (BR), the only protein in PM, causes the formation of blue membrane (BM), which is accompanied by a loss of β-sheet structure observable in the infrared spectrum. Glassy sugars are particular useful to observe this transition, as sugar entrapment does not restrict conformational changes of BR but rather retards them. The material obtained was named sugar-induced blue membrane (SIBM). The formation of SIBM is inhibited by the addition of divalent cations. Furthermore, SIBM is reverted immediately to PM by addition of water. A characteristic time dependence of the thermal reversion of SIBM to PM proves that the phase transition of PM triggers the release and uptake of divalent cations and the corresponding color change.