Quantum transduction from electron spin state to signaling in wild-type AsLOV2
- 1Northwestern University
Abstract
Coherent electron-spin dynamics has been shown to modulate flavoprotein fluorescence in vivo, but not the chemistry by which a protein signals. Here we show that a magnetic field modulates formation of the covalent FMN-cysteine photoadduct that constitutes the signaling state of wild-type Avena sativa LOV2 (AsLOV2), via a spin-selective radical-pair reaction. AsLOV2 was thought magnetically inactive, but a fluorescence magnetic field effect (MFE) emerges near 100 mT and reaches 7% by 1300 mT. Tracking the photoadduct by UV-vis absorption, we find that 650 mT raises the signaling state population and shortens the product formation time constant by 6.7 +/- 0.6%. The short FMN-cysteine separation produces a large dipolar coupling that blocks hyperfine-driven triplet-singlet interconversion at low field; the unusually large flavin-cysteinyl radical g-factor difference overcomes it at high field. The same proximity enables covalent bond formation of radical pairs in a singlet state. This arrangement is canonical in LOV domains, so magnetically enhanced signaling likely extends across natural and engineered photoreceptors
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BibTeX
@misc{salvia2026quantum,
title = {{Quantum transduction from electron spin state to signaling in wild-type AsLOV2}},
author = {W. Salvia and J. Straub and S. Maity and A. Bogdanov and S. Chaudhuri and R. Han and S. Han},
howpublished = {bioRxiv},
year = {2026},
month = jun,
doi = {10.64898/2026.06.30.735402},
url = {https://www.biorxiv.org/content/10.64898/2026.06.30.735402v2},
note = {CC BY},
}
RIS
TY - UNPB
TI - Quantum transduction from electron spin state to signaling in wild-type AsLOV2
AU - W. Salvia
AU - J. Straub
AU - S. Maity
AU - A. Bogdanov
AU - S. Chaudhuri
AU - R. Han
AU - S. Han
PY - 2026
DA - 2026/06/30
PB - bioRxiv
DO - 10.64898/2026.06.30.735402
UR - https://www.biorxiv.org/content/10.64898/2026.06.30.735402v2
AB - Coherent electron-spin dynamics has been shown to modulate flavoprotein fluorescence in vivo, but not the chemistry by which a protein signals. Here we show that a magnetic field modulates formation of the covalent FMN-cysteine photoadduct that constitutes the signaling state of wild-type Avena sativa LOV2 (AsLOV2), via a spin-selective radical-pair reaction. AsLOV2 was thought magnetically inactive, but a fluorescence magnetic field effect (MFE) emerges near 100 mT and reaches 7% by 1300 mT. Tracking the photoadduct by UV-vis absorption, we find that 650 mT raises the signaling state population and shortens the product formation time constant by 6.7 +/- 0.6%. The short FMN-cysteine separation produces a large dipolar coupling that blocks hyperfine-driven triplet-singlet interconversion at low field; the unusually large flavin-cysteinyl radical g-factor difference overcomes it at high field. The same proximity enables covalent bond formation of radical pairs in a singlet state. This arrangement is canonical in LOV domains, so magnetically enhanced signaling likely extends across natural and engineered photoreceptors
ER -