Issue 43, 2018

Different hydrogen bonding environments of the retinal protonated Schiff base control the photoisomerization in channelrhodopsin-2

Abstract

The first event of the channelrhodopsin-2 (ChR2) photocycle, i.e. trans-to-cis photoisomerization, is studied by means of quantum mechanics/molecular mechanics, taking into account the flexible retinal environment in the ground state. By treating the chromophore at the ab initio multiconfigurational level of theory, we can rationalize the experimental findings based on pump–probe spectroscopy, explaining the different and more complex scenario found for ChR2 in comparison to other rhodopsins. In particular, we find that depending on the hydrogen bonding pattern, different excited states are involved, hence making it possible to suggest one pattern as the most productive. Moreover, after photoisomerization the structure of the first photocycle intermediate, P5001, is characterized by simulating the infrared spectrum and compared to available experimental data. This was obtained by extensive molecular dynamics, where the chromophore is described by a semi-empirical method based on density functional theory. The results clearly identify which counterion is responsible for accepting the proton from the retinal Schiff base: the side chain of the glutamic acid E123.

Graphical abstract: Different hydrogen bonding environments of the retinal protonated Schiff base control the photoisomerization in channelrhodopsin-2

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
15 Aug 2018
Accepted
11 Oct 2018
First published
11 Oct 2018

Phys. Chem. Chem. Phys., 2018,20, 27501-27509

Different hydrogen bonding environments of the retinal protonated Schiff base control the photoisomerization in channelrhodopsin-2

Y. Guo, F. E. Wolff, I. Schapiro, M. Elstner and M. Marazzi, Phys. Chem. Chem. Phys., 2018, 20, 27501 DOI: 10.1039/C8CP05210G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements