Speaker
Description
Life is governed not only by classical physics but also by quantum mechanics, especially in processes involving electron transitions. While all chemical reactions involve quantum phenomena, some biological systems appear to exploit them in surprising ways. A striking example is the ability of migratory birds to sense Earth’s magnetic field, plausibly via light-induced, spin-correlated radical pairs formed in retinal cryptochromes [1,2].
In this talk, I will discuss how such radical pairs may act as a "chemical compass" [3]. I will outline the fundamental reaction steps in cryptochrome activation and deactivation, emphasizing how the interplay between protein structure, cofactors, and magnetic interactions possibly shapes spin dynamics and magnetic sensitivity of the protein [1,4,5]. Because proteins are dynamic, thermal motions modulate local interactions and drive spin relaxation, which can both degrade coherence and, under some conditions, tune sensitivity. Molecular dynamics simulations based on three-dimensional cryptochrome structures provide a way to examine these fluctuations and their consequences for radical-pair behavior [1,4–6].
Theoretical approaches, including Redfield theory and stochastic Schrödinger dynamics, will also be discussed in the context of describing how environmental noise and molecular motion affect spin coherence in biological systems [7,8], alongside the use of modern computational platforms to implement such models efficiently [9]. I will close by highlighting broader implications for spin dynamics and possible quantum effects in biological chemistry beyond avian magnetoreception.
References:
[1] J. Xu, et al., Nature, 2021, 594, 535–540.
[2] D. Timmer, A. Frederiksen, D. C. Lünemann, A. R. Thomas, J. Xu, R. Bartölke, J. Schmidt, T. Kubař, A. D. Sio, I. A. Solov’yov, et al., J. Am. Chem. Soc., 2023, 145, 11566–11578.
[3] S. Y. Wong, A. Frederiksen, M. Hanić, et al., Neuroforum, 2021, 27 141–150.
[4] F. Schuhmann, D. R. Kattnig, I. A. Solov’yov, J. Phys. Chem. B, 2021, 125, 9652–9659.
[5] F. Schuhmann, et al., J. Phys. Chem. B, 2024, 128, 3844–3855.
[6] G. Grüning, S. Y. Wong, L. Gerhards, et al., J. Am. Chem. Soc., 2022, 144, 22902–22914.
[7] L. Gerhards, C. Nielsen, D. R. Kattnig, et al., J. Comp. Chem., 2023, 44, 1704–1714.
[8] G. Jurgis Pažera, T.P. Fay, I.A. Solov’yov, et al., J. Chem. Theor. Comp. 2024, 20, 8412–8421 (2024).
[9] V. Korol, P. Husen, E. Sjulstok, et al., ACS Omega, 2020, 5, 1254–1260.