Institute of Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.
Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
Angew Chem Int Ed Engl. 2021 Jul 19;60(30):16442-16447. doi: 10.1002/anie.202015797. Epub 2021 Jun 17.
Channelrhodopsin-2 (ChR2) is a light-gated cation channel and was used to lay the foundations of optogenetics. Its dark state X-ray structure has been determined in 2017 for the wild-type, which is the prototype for all other ChR variants. However, the mechanistic understanding of the channel function is still incomplete in terms of structural changes after photon absorption by the retinal chromophore and in the framework of functional models. Hence, detailed information needs to be collected on the dark state as well as on the different photointermediates. For ChR2 detailed knowledge on the chromophore configuration in the different states is still missing and a consensus has not been achieved. Using DNP-enhanced solid-state MAS NMR spectroscopy on proteoliposome samples, we unambiguously determined the chromophore configuration in the desensitized state, and we show that this state occurs towards the end of the photocycle.
通道视紫红质 2（ChR2）是一种光门控阳离子通道，被用于奠定光遗传学的基础。其暗态 X 射线结构已于 2017 年确定为野生型，这是所有其他 ChR 变体的原型。然而，在吸收光后视网膜色素的结构变化以及功能模型方面，通道功能的机制理解仍不完整。因此，需要详细收集有关暗态以及不同光中间产物的信息。对于 ChR2，关于不同状态下的发色团构型的详细信息仍然缺失，并且尚未达成共识。使用 DNP 增强的固态 MAS NMR 光谱法对脂质体样品进行研究，我们明确确定了脱敏状态下的发色团构型，并表明该状态发生在光循环的末期。
