通过纳米秒红外光谱学监测的Channelrhodopsin-2的ChETA变体中的预定性构造变化
Víctor A Lórenz-Fonfría1, Bernd-Joachim Schultz, Tom Resler
1Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin , Arnimallee 14, 14195 Berlin, Germany.
Journal of the American Chemical Society
|January 14, 2015
概括
我们使用先进的光谱学研究了channelrhodopsin-2 (ChR2) 的光循环. 快速循环的ChETA变体揭示了预开口的形状变化,并澄清了视网膜异构体在通道功能中的作用.
科学领域:
- 生物物理学的生物物理.
- 摄影化学的使用.
- 分子生物学分子生物学
背景情况:
- 道罗多普辛-2 (ChR2) 通过视网膜光异构化促进光离子运输.
- 了解ChR2光循环对于光遗传学和神经科学应用至关重要.
- 像ChETA这样的快速循环变体提供了研究快速功能动态的机会.
研究的目的:
- 为了阐明快速循环的ChR2变体,ChETA的光周期中的早期事件和构造变化.
- 为了区分所有跨和13-cis视网膜异构体对ChR2光循环的贡献.
- 解决中间状态的动力学及其功能相关性.
主要方法:
- 时间分辨率UV/V光谱学.
- 步骤扫描里埃变换红外 (FT-IR) 光谱学.
- 可调的量子级联激光IR光谱与纳米秒分辨率.
主要成果:
- 确定了在200 ns内发生的预定性构造变化,涉及骨和D156残留H键,可通过IR检测,但不能通过UV/Vis检测.
- 解决了P1(500) 的中间状态,将其分为不同的早期和晚期状态.
- 证明全跨和13-cis视网膜都在适应光的ChR2.2中具有光活性.
- 确定13-cis光循环在1ms内恢复,比通道门和质子转移更快.
结论:
- 由于其快速恢复,ChR2的13-cis光循环在功能上不那么重要.
- 早期的形状变化先于通道开放,对于理解CHR2门的理解至关重要.
- 对ChETA的光谱洞察力有助于我们更好地理解道罗多普辛的光物理和功能.
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