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Structural differences between the closed and open states of channelrhodopsin‐2 as observed by EPR spectroscopy
Author(s) -
Krause Nils,
Engelhard Christopher,
Heberle Joachim,
Schlesinger Ramona,
Bittl Robert
Publication year - 2013
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2013.08.043
Subject(s) - electron paramagnetic resonance , site directed spin labeling , chemistry , dimer , spectroscopy , channelrhodopsin , crystallography , nuclear magnetic resonance spectroscopy , spin states , intermolecular force , stereochemistry , nuclear magnetic resonance , molecule , physics , optogenetics , inorganic chemistry , organic chemistry , quantum mechanics , neuroscience , biology
Channelrhodopsin is a cation channel with the unique property of being activated by light. To address structural changes of the open state of the channel, two variants, which contain either 1 or 2 wild‐type cysteines, were derivatised with nitroxide spin label and subjected to electron paramagnetic resonance spectroscopy. Both variants contained the C128T mutation to trap the long‐livedP 3 520state by illumination. Comparison of spin–spin distances in the dark state and after illumination reflect conformational changes in the conductiveP 3 520state involving helices B and F. Spin distance measurements reveal that channelrhodopsin forms a dimer even in the absence of intermolecular N‐terminal cysteines.