Specific residues in the cytoplasmic domain modulate photocurrent kinetics of channelrhodopsin from Klebsormidium nitens.
Commun Biol
; 4(1): 235, 2021 02 23.
Article
em En
| MEDLINE
| ID: mdl-33623126
ABSTRACT
Channelrhodopsins (ChRs) are light-gated ion channels extensively applied as optogenetics tools for manipulating neuronal activity. All currently known ChRs comprise a large cytoplasmic domain, whose function is elusive. Here, we report the cation channel properties of KnChR, one of the photoreceptors from a filamentous terrestrial alga Klebsormidium nitens, and demonstrate that the cytoplasmic domain of KnChR modulates the ion channel properties. KnChR is constituted of a 7-transmembrane domain forming a channel pore, followed by a C-terminus moiety encoding a peptidoglycan binding domain (FimV). Notably, the channel closure rate was affected by the C-terminus moiety. Truncation of the moiety to various lengths prolonged the channel open lifetime by more than 10-fold. Two Arginine residues (R287 and R291) are crucial for altering the photocurrent kinetics. We propose that electrostatic interaction between the rhodopsin domain and the C-terminus domain accelerates the channel kinetics. Additionally, maximal sensitivity was exhibited at 430 and 460 nm, the former making KnChR one of the most blue-shifted ChRs characterized thus far, serving as a novel prototype for studying the molecular mechanism of color tuning of the ChRs. Furthermore, KnChR would expand the optogenetics tool kit, especially for dual light applications when short-wavelength excitation is required.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Ativação do Canal Iônico
/
Clorófitas
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Channelrhodopsins
Limite:
Animals
Idioma:
En
Revista:
Commun Biol
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Japão