Details

Autor(en) / Beteiligte

• Liang, Ruibin
• Liu, Fang
• Martínez, Todd J

Titel

Nonadiabatic Photodynamics of Retinal Protonated Schiff Base in Channelrhodopsin 2

Ist Teil von

• The journal of physical chemistry letters, 2019-06, Vol.10 (11), p.2862-2868

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Channelrhodopsin 2 (ChR2) is a light-gated ion channel and an important tool in optogenetics. Photoisomerization of retinal protonated Schiff base (RPSB) in ChR2 triggers channel activation. Despite the importance of ChR2 in optogenetics, the detailed mechanism for photoisomerization and channel activation is still not fully understood. Here, we report on computer simulations to investigate the photoisomerization mechanism and its effect on the activation of ChR2. Nonadiabatic dynamics simulation of ChR2 was carried out using the ab initio multiple spawning (AIMS) method and quantum mechanics/molecular mechanics (QM/MM) with a restricted ensemble Kohn–Sham (REKS) treatment of the QM region. Our results agree well with spectroscopic measurements and reveal that the RPSB isomerization is highly specific around the C13=C14 bond and follows the “aborted bicycle-pedal” mechanism. In addition, RPSB photoisomerization facilitates its deprotonation and partially increases the hydration level in the channel, which could trigger subsequent channel opening and ion conduction.