University of Oulu

Serge G. Sokolovski, Evgeny A. Zherebtsov, Rajiv K. Kar, David Golonka, Robert Stabel, Nikolai B. Chichkov, Andrei Gorodetsky, Igor Schapiro, Andreas Möglich, Edik U. Rafailov, Two-photon conversion of a bacterial phytochrome, Biophysical Journal, Volume 120, Issue 5, 2021, Pages 964-974, ISSN 0006-3495,

Two-photon conversion of a bacterial phytochrome

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Author: Sokolovski, Serge G.1; Zherebtsov, Evgeny A.2,3; Kar, Rajiv K.4;
Organizations: 1Optoelectronics and Biomedical Photonics Group, AIPT, Aston University, Birmingham, United Kingdom
2Optoelectronics and Measurement Techniques, University of Oulu, Oulu, Finland
3Cell Physiology and Pathology Laboratory, Orel State University, Orel, Russia
4Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
5Photobiochemistry, University of Bayreuth, Bayreuth, Germany
6ITMO University, St. Petersburg, Russia
7Department of Chemistry, Imperial College London, London, United Kingdom
8School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.9 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2022-03-14


In nature, sensory photoreceptors underlie diverse spatiotemporally precise and generally reversible biological responses to light. Photoreceptors also serve as genetically encoded agents in optogenetics to control by light organismal state and behavior. Phytochromes represent a superfamily of photoreceptors that transition between states absorbing red light (Pr) and far-red light (Pfr), thus expanding the spectral range of optogenetics to the near-infrared range. Although light of these colors exhibits superior penetration of soft tissue, the transmission through bone and skull is poor. To overcome this fundamental challenge, we explore the activation of a bacterial phytochrome by a femtosecond laser emitting in the 1 μm wavelength range. Quantum chemical calculations predict that bacterial phytochromes possess substantial two-photon absorption cross sections. In line with this notion, we demonstrate that the photoreversible Pr ↔ Pfr conversion is driven by two-photon absorption at wavelengths between 1170 and 1450 nm. The Pfr yield was highest for wavelengths between 1170 and 1280 nm and rapidly plummeted beyond 1300 nm. By combining two-photon activation with bacterial phytochromes, we lay the foundation for enhanced spatial resolution in optogenetics and unprecedented penetration through bone, skull, and soft tissue.

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Series: Biophysical journal
ISSN: 0006-3495
ISSN-E: 1542-0086
ISSN-L: 0006-3495
Volume: 120
Issue: 5
Pages: 964 - 974
DOI: 10.1016/j.bpj.2021.01.028
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Funding: This project has received funding from the European Union’s H2020 FET OPEN NEUROPA project under the grant agreement no. 863214 (E.U.R., S.G.S., and A.M). A.M. gratefully acknowledges funding by the Deutsche Forschungsgemeinschaft (grants MO2192/4-1 and MO2192/7-1). I.S. acknowledges funding by the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant no. 678169 ‘‘PhotoMutant’’). I.S. thanks the SFB 1078 “Protonation Dynamics in Protein Function” for the Mercator fellowship. R.K.K. acknowledges support from the Lady Davis Trust for the Shunbrun postdoctoral fellowship. N.B.C. has received funding from the EU H2020 research and innovation program under the Marie Skłodowska-Curie (grant agreement no. 843801); E.A.Z. acknowledges funding by the Academy of Finland (grant 318281), RFBR (grant 20-08-01153∖20), Russian Science Foundation (grant 20-75-00123), and the grant of the Russian Federation Government no. 075-15-2019-1877.
EU Grant Number: (863214) NEUROPA - Non-invasive dynamic neural control by laser-based technology
Copyright information: © 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license by