סמינר מיוחד בכימיה פיזיקלית: Transient Spin Interactions in Chiral Biochemical Systems

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Abstract:

Life’s biochemical architecture is fundamentally chiral: biological molecules exist as two non-superimposable mirror-image forms called enantiomers. Life on Earth consistently uses only one of these forms, a phenomenon called homochirality, yet its origins and persistence through evolution remain unresolved.

When molecules interact with each other or with surfaces, charge displacement occurs. In chiral molecules, the rate of this electron displacement depends on the electron’s spin, a phenomenon known as chirality-induced spin selectivity (CISS) [1]. This effect gives rise to transient spin polarization in chiral molecules, resulting in strong, directional, spin-dependent enantiospecific interactions that may be fundamental to life’s molecular structure and function [2].

In my talk, I will discuss how RNA precursors can locally magnetize mineral surfaces in early-Earth shallow lakes, amplifying the natural magnetization induced by the Earth’s magnetic field. This reveals a self-reinforcing feedback loop between chiral molecules and magnetic surfaces, which can significantly break chiral symmetry and cause homochirality to emerge under prebiotically plausible conditions[3]. Unexpectedly, we also found that the induced magnetization increased with temperature, suggesting a vibronic contribution to CISS [4]. This indicates that spin-controlled mechanisms may operate robustly under realistic, variable prebiotic conditions.

Finally, I extend this framework to dynamic biological systems by investigating whether this interaction could influence amyloid self-assembly, a process associated with neurodegenerative diseases. We demonstrated that magnetized substrates alter the formation dynamics of amyloid fibrils, suggesting that spin polarization plays a role in pathological protein aggregation due to the CISS effect [5]. These findings open the door to spin-based strategies for probing or controlling neurodegenerative disease mechanisms.

1. Naaman, R., Paltiel, Y. et al. Nature Reviews Chemistry, 3, 250–260 (2019).

2. Kapon, Y., Saha, A., Duanis-Assaf, T. et al. Chem, 7(10), 2787–2799 (2021).

3. Ozturk, S. F., Bhowmick, D. K., Kapon, Y., et al. Nature Communications, 14(1), 6351 (2023).

4. Kapon, Y., Brann, L., Yochelis, S. et al. arXiv preprint arXiv:2412.05720 (2024).
In review in Cell Reports Physical Science.

5. Kapon, Y., Merhav, D., Finkelstein-Zuta, G. et al. arXiv preprint arXiv:2503.06265 (2025). In review in ACS Nano.

מארגן הסמינר: פרופ' יובל אבנשטיין