TY - JOUR
T1 - Structural Insights Into the Opening Mechanism of C1C2 Channelrhodopsin
AU - Mulder, Matthias
AU - Hwang, Songhwan
AU - Broser, Matthias
AU - Brünle, Steffen
AU - Skopintsev, Petr
AU - Schattenberg, Caspar
AU - Schnick, Christina
AU - Hartmann, Sina
AU - Church, Jonathan
AU - Schapiro, Igor
AU - Dworkowski, Florian
AU - Weinert, Tobias
AU - Hegemann, Peter
AU - Sun, Han
AU - Standfuss, Jörg
N1 - Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.
PY - 2024
Y1 - 2024
N2 - Channelrhodopsins, light-gated cation channels, enable precise control of neural cell depolarization or hyperpolarization with light in the field of optogenetics. This study integrates time-resolved serial crystallography and atomistic molecular dynamics (MD) simulations to resolve the structural changes during C1C2 channelrhodopsin activation. Our observations reveal that within the crystal environment, C1C2 predominantly remains in a light-activated state with characteristics of the M390 intermediate. Here, rearrangement of retinal within its binding pocket partially opens the central gate toward the extracellular vestibule. These structural changes initiate channel opening but were insufficient to allow K+ flow. Adjusting protonation states to represent the subsequent N520 intermediate in our MD simulations induced further conformational changes, including rearrangements of transmembrane helices 2 and 7, that opened the inner gate and the putative ion-translocation pathway. This allowed spontaneous cation conduction with low conductance, aligning with experimental findings. Our findings provide critical structural insights into key intermediates of the channel opening mechanism, enhancing our understanding of ion conduction and selectivity in channelrhodopsins at an atomistic level.
AB - Channelrhodopsins, light-gated cation channels, enable precise control of neural cell depolarization or hyperpolarization with light in the field of optogenetics. This study integrates time-resolved serial crystallography and atomistic molecular dynamics (MD) simulations to resolve the structural changes during C1C2 channelrhodopsin activation. Our observations reveal that within the crystal environment, C1C2 predominantly remains in a light-activated state with characteristics of the M390 intermediate. Here, rearrangement of retinal within its binding pocket partially opens the central gate toward the extracellular vestibule. These structural changes initiate channel opening but were insufficient to allow K+ flow. Adjusting protonation states to represent the subsequent N520 intermediate in our MD simulations induced further conformational changes, including rearrangements of transmembrane helices 2 and 7, that opened the inner gate and the putative ion-translocation pathway. This allowed spontaneous cation conduction with low conductance, aligning with experimental findings. Our findings provide critical structural insights into key intermediates of the channel opening mechanism, enhancing our understanding of ion conduction and selectivity in channelrhodopsins at an atomistic level.
UR - http://www.scopus.com/inward/record.url?scp=85212324472&partnerID=8YFLogxK
U2 - 10.1021/jacs.4c15402
DO - 10.1021/jacs.4c15402
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C2 - 39680650
AN - SCOPUS:85212324472
SN - 0002-7863
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
ER -