Experimentelle Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin Berlin, Germany.
Methods for Material Development, Helmholtz-Zentrum für Materialien und Energie GmbH Berlin, Germany.
Front Mol Biosci. 2015 Jul 7;2:38. doi: 10.3389/fmolb.2015.00038. eCollection 2015.
Among optogenetic tools, channelrhodopsins, the light gated ion channels of the plasma membrane from green algae, play the most important role. Properties like channel selectivity, timing parameters or color can be influenced by the exchange of selected amino acids. Although widely used, in the field of neurosciences for example, there is still little known about their photocycles and the mechanism of ion channel gating and conductance. One of the preferred methods for these studies is infrared spectroscopy since it allows observation of proteins and their function at a molecular level and in near-native environment. The absorption of a photon in channelrhodopsin leads to retinal isomerization within femtoseconds, the conductive states are reached in the microsecond time scale and the return into the fully dark-adapted state may take more than minutes. To be able to cover all these time regimes, a range of different spectroscopical approaches are necessary. This mini-review focuses on time-resolved applications of the infrared technique to study channelrhodopsins and other light triggered proteins. We will discuss the approaches with respect to their suitability to the investigation of channelrhodopsin and related proteins.
在光遗传学工具中，通道蛋白视紫红质（ChR）是来自绿藻的质膜光门控离子通道，起着最重要的作用。通过交换选定的氨基酸，可以影响通道的选择性、时间参数或颜色等特性。尽管在神经科学等领域得到了广泛应用，但对于它们的光循环以及离子通道门控和电导的机制，人们仍然知之甚少。对于这些研究，其中一种首选的方法是红外光谱法，因为它可以在接近天然环境的条件下，在分子水平上观察蛋白质及其功能。通道蛋白视紫红质吸收光子后，会在飞秒内引发视黄醛异构化，导电状态会在微秒时间尺度内达到，而完全恢复到黑暗适应状态可能需要几分钟时间。为了能够涵盖所有这些时间范围，需要使用一系列不同的光谱方法。这篇迷你综述重点介绍了红外技术在研究通道蛋白视紫红质和其他光触发蛋白方面的时间分辨应用。我们将根据它们对通道蛋白视紫红质和相关蛋白的适用性来讨论这些方法。
