Structural differences between the closed and open states of channelrhodopsin‐2 as observed by EPR spectroscopy. Issue 20 (10th September 2013)

• Record Type: Journal Article
• Authors: Krause, Nils; Engelhard, Christopher; Heberle, Joachim; Schlesinger, Ramona; Bittl, Robert
• Is Part Of: FEBS letters. Volume 587:Issue 20(2013)
• Page Start: 3309
• Page End: 3313
• Publication Date: 2013-09-10
• Subjects: ChR2 -- channelrhodopsin 2 -- SRII -- sensory rhodopsin II -- BR -- bacteriorhodopsin -- EPR -- electron paramagnetic resonance -- cw-EPR -- continuous wave electron paramagnetic resonance -- pELDOR -- pulsed electron–electron double resonance -- DEER -- double electron–electron resonance -- MTSL -- (1-oxyl-2, 2, 5, 5-tetramethylpyrroline-3-methyl)methanethiosulfonate spin label -- MES -- 2-(N-morpholino)ethanesulfonic acid -- DM -- decyl-β-d-maltoside -- Optogenetic -- Rhodopsin -- Light-activated cation channel -- Photocycle -- Membrane protein -- EPR spectroscopy; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1016/j.febslet.2013.08.043
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : 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‐lived P 3 520 state by illumination. Comparison of spin–spin distances in the dark state and after illumination reflect conformational changes in the conductive P 3 520 state involving helices B and F. Spin distance measurements reveal that channelrhodopsin forms a dimer even in the absence of intermolecular N‐terminal cysteines. Abstract : We find specific dimerization independent of cysteine residues. ChR2 shows a structural change in helix F upon light excitation as in other retinal proteins. We find additional structural changes in either helix B or the dimerization interface.