Humboldt-Universität zu Berlin - Experimentelle Biophysik

Structure and function of novel photoreceptor proteins

As part of the Hegemann group, we are interested in studying how absorption of photon induces structural changes in photoreceptor proteins, including, microbial rhodopsins, rhodopsin fusion proteins such as enzymerhodopsins and bestrhodopsins.

One of our current research projects aims to elucidate the cryo-EM structure and function of enzymerhodopsins, which are a class of light-regulated photoreceptor fusion proteins that have a rhodopsin domain fused to an enzyme domain. They function as light-controlled catalysts, with known examples including rhodopsin phosphodiesterases (RhoPDEs), rhodopsin guanylyl cyclases (RhGCs), and histidine kinase rhodopsins (HKRs). These proteins have significant potential for use in optogenetics, as they can be used to optically manipulate cellular processes, such as the production or breakdown of cyclic nucleotides.

We are also studying the molecular mechanism of photochemistry and thermal stability of microbial rhodopsin. Given that the light-induced photocycle initiates their biological functions, ranging from outward proton pumping, ion transport, and so on in these proteins, we employ various time-resolved spectoscopic tools to understand the factors affecting their photochemistry at the molecular level. In collaboration with other groups, we are also involved in in-silico design of novel intramolecular charge transfer (ICT)-based chromophores for future technological applications.

Current co-workers: Ms. Melisa Güler (Student research assistant)

Ms. Antoinette Ngyuen (Technical Assistant)

We periodically publish opportunities for Masters thesis/ Masters Student assistant (Deutsch: Studentische Hilfskraft) positions. Please check open position section in the Hegemann group page periodically, and feel free contact us for any enquiry.

Publications

R. Misra, I. Das, A. Dér, G. Steinbach, J.-g. Shim, W. Busse, K.-H. Jung, L. Zimányi, M. Sheves,Impact of Protein-Retinal Interaction on the Retinal Excited State and Photocycle of Gloeobacter Rhodopsin: Role of Conserved Tryptophan Residues. Chemical Science 2023. https://doi.org/10.1039/D3SC02961A

Ghosh, M.; Misra, R.; Jung, K.H.; Sheves, M. Retinal-Carotenoid Interactions in a Sodium Ion-Pumping Rhodopsin: Implications on Oligomerization and Thermal Stability. The Journal of Physical Chemistry B 2023.  https://doi.org/10.1021/acs.jpcb.2c07502

Samanta, P.K.; Misra, R. Intramolecular Charge Transfer for Optical Applications. Journal of Applied Physics 2023, 133, 020901. (Invited perspective; Featured in 2022 Early Career Investigator Selection collection) https://doi.org/10.1063/5.0131426

Misra, R.; Hirshfeld, A.; Sheves. M. Molecular Mechanism for Thermal Denaturation of Thermophilic Rhodopsin. Chemical Science 2019, 10, 7365-7374. http://dx.doi.org/10.1039/C9SC00855A

Misra, R.; Eliash, T.; Sudo, Y.; Sheves. M. Carotenoid-retinal Interaction in a Thermophilic Rhodopsin. Journal of Physical Chemistry B 2019, 123, 10-20. https://doi.org/10.1021/acs.jpcb.8b06795

Misra R., Bhattacharyya S.P. , Intramolecular Charge Transfer: Theory and Applications, , 2018, Wiley‐VCH Verlag GmbH. DOI:10.1002/9783527801916

Iyer, E.S.S.; Misra, R.; Maity, A.; Liubashevski, O.; Sudo, Y.; Sheves, M.; Ruhman, S. Temperature Independence of Ultrafast Photo-isomerization in Thermophilic Rhodopsin: Assessment vs Other Microbial Proton Pumps. Journal of the American Chemical Society 2016, 138, 12401-12407.

https://doi.org/10.1021/jacs.6b05002