The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity
The primary photodynamics of channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) was investigated by VIS-pump supercontinuum probe experiments from femtoseconds to 100 picoseconds. In contrast to reported experiments on channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2), we found a clear...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Frontiers Media S.A.
2015-07-01
|
Series: | Frontiers in Molecular Biosciences |
Subjects: | |
Online Access: | http://journal.frontiersin.org/Journal/10.3389/fmolb.2015.00041/full |
id |
doaj-4f3ef94e0bb141efbed96486b91b17e2 |
---|---|
record_format |
Article |
spelling |
doaj-4f3ef94e0bb141efbed96486b91b17e22020-11-24T22:59:05ZengFrontiers Media S.A.Frontiers in Molecular Biosciences2296-889X2015-07-01210.3389/fmolb.2015.00041146236The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneityKarsten eHeyne0Till eStensitzki1Vera eMuders2Joachim eHeberle3Ramona eSchlesinger4Free University BerlinFree University BerlinFree University BerlinFree University BerlinFree University BerlinThe primary photodynamics of channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) was investigated by VIS-pump supercontinuum probe experiments from femtoseconds to 100 picoseconds. In contrast to reported experiments on channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2), we found a clear dependence of the photoreaction dynamics on varying the excitation wavelength. Upon excitation at 500 nm and at 550 nm we detected different bleaching bands, andspectrally distinct photoproduct absorptions in the first picoseconds. We assign the former to the ground-state heterogeneity of a mixture of 13-cis and all-trans retinal maximally absorbing around 480 nm and 540 nm, respectively. At 550 nm, all-trans retinal of the ground state is almost exclusively excited. Here, we found a fast all-trans to 13-cis isomerization process to a hot and spectrally broad P1 photoproduct with a time constant of (100±50) fs, followed by photoproduct relaxation with time constants of (500±100) fs and (5±1) ps. The remaining fraction relaxes back to the parent ground state with time constants of (500±100) fs and (5±1) ps. Upon excitation at 500 nm a mixture of both chromophore conformations is excited, resulting in overlapping reaction dynamics with additional time constants of <300 fs, (1.8±0.3) ps and (90±25) ps. A new photoproduct Q is formed absorbing at around 600 nm. Strong coherent oscillatory signals were found pertaining up to several picoseconds. We determined low frequency modes around 200 cm-1, similar to those reported for bacteriorhodopsin.http://journal.frontiersin.org/Journal/10.3389/fmolb.2015.00041/fullRetinalisomerizationReaction modelFemtosecond pump-probe spectroscopyCaChR1ground state heterogeneity |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Karsten eHeyne Till eStensitzki Vera eMuders Joachim eHeberle Ramona eSchlesinger |
spellingShingle |
Karsten eHeyne Till eStensitzki Vera eMuders Joachim eHeberle Ramona eSchlesinger The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity Frontiers in Molecular Biosciences Retinal isomerization Reaction model Femtosecond pump-probe spectroscopy CaChR1 ground state heterogeneity |
author_facet |
Karsten eHeyne Till eStensitzki Vera eMuders Joachim eHeberle Ramona eSchlesinger |
author_sort |
Karsten eHeyne |
title |
The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity |
title_short |
The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity |
title_full |
The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity |
title_fullStr |
The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity |
title_full_unstemmed |
The primary photoreaction of channelrhodopsin-1: Wavelength dependent photoreactions induced by ground-state heterogeneity |
title_sort |
primary photoreaction of channelrhodopsin-1: wavelength dependent photoreactions induced by ground-state heterogeneity |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Molecular Biosciences |
issn |
2296-889X |
publishDate |
2015-07-01 |
description |
The primary photodynamics of channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) was investigated by VIS-pump supercontinuum probe experiments from femtoseconds to 100 picoseconds. In contrast to reported experiments on channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2), we found a clear dependence of the photoreaction dynamics on varying the excitation wavelength. Upon excitation at 500 nm and at 550 nm we detected different bleaching bands, andspectrally distinct photoproduct absorptions in the first picoseconds. We assign the former to the ground-state heterogeneity of a mixture of 13-cis and all-trans retinal maximally absorbing around 480 nm and 540 nm, respectively. At 550 nm, all-trans retinal of the ground state is almost exclusively excited. Here, we found a fast all-trans to 13-cis isomerization process to a hot and spectrally broad P1 photoproduct with a time constant of (100±50) fs, followed by photoproduct relaxation with time constants of (500±100) fs and (5±1) ps. The remaining fraction relaxes back to the parent ground state with time constants of (500±100) fs and (5±1) ps. Upon excitation at 500 nm a mixture of both chromophore conformations is excited, resulting in overlapping reaction dynamics with additional time constants of <300 fs, (1.8±0.3) ps and (90±25) ps. A new photoproduct Q is formed absorbing at around 600 nm. Strong coherent oscillatory signals were found pertaining up to several picoseconds. We determined low frequency modes around 200 cm-1, similar to those reported for bacteriorhodopsin. |
topic |
Retinal isomerization Reaction model Femtosecond pump-probe spectroscopy CaChR1 ground state heterogeneity |
url |
http://journal.frontiersin.org/Journal/10.3389/fmolb.2015.00041/full |
work_keys_str_mv |
AT karsteneheyne theprimaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT tillestensitzki theprimaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT veraemuders theprimaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT joachimeheberle theprimaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT ramonaeschlesinger theprimaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT karsteneheyne primaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT tillestensitzki primaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT veraemuders primaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT joachimeheberle primaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity AT ramonaeschlesinger primaryphotoreactionofchannelrhodopsin1wavelengthdependentphotoreactionsinducedbygroundstateheterogeneity |
_version_ |
1725645720827985920 |