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Researchers discovered that naturally occurring LOV protein domains from halophilic archaea that lack a conserved cysteine amino acid exhibit magnetic field effects on their fluorescence through the radical pair mechanism. Using a custom imaging platform, they found that HsuLOV from a halophilic archaeon and a mutant of BAT-LOV from another halophilic archaeon showed magneto-fluorescence when exposed to switched magnetic fields, while amb2291 from magnetotactic bacteria did not respond under the tested conditions. These represent the first magnetosensitive proteins identified from the archaea domain of life, suggesting this property may be more common in nature than previously thought.
Why it matters
This discovery expands our understanding of how magnetic fields can influence biological systems and suggests that radical-pair magnetosensitivity may be widespread in nature. The findings could inform future research on biological magnetoreception and potential biotechnological applications involving magnetically-controllable fluorescent proteins.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Magnetic fields can modulate the function of certain flavoproteins through the radical pair mechanism, in which they influence the spin evolution of a coherent pair of radicals. This process can result in magneto-fluorescence, in which magnetic fields modulate the intensity of fluorescence emitted from the flavin cofactor. The prevalence of this property across protein families and domains of life, however, remains poorly characterized. In canonical Light-Oxygen-Voltage (LOV) domains, a conserved cysteine forms an adduct with the flavin that leads to downstream signaling. Mutating this cysteine instead yields signaling through the neutral semiquinone radical form, and the same mutation was crucial for enhancing magneto-fluorescence in the engineered protein MagLOV2. We therefore hypothesized that natural LOV domains that lack this conserved cysteine may exhibit magneto-fluorescence. Using a custom magneto-fluorescence imaging platform, we measured the fluorescence of E. coli colonies expressing three such domains, as well as a single mutant of one of them, under a switched external field. HsuLOV, from a halophilic archaeon, exhibited magneto-fluorescence, as did a single mutant of BAT-LOV, from a second halophilic archaeon. The domain amb2291 from magnetotactic bacteria, on the other hand, showed no detectable response under our illumination conditions. Magneto-fluorescence is therefore not exclusive to engineered proteins but is present in natural cysteine-less LOV domain sequences. The proteins reported here are, to our knowledge, the first magnetosensitive proteins reported from archaea. This suggests that radical-pair magnetosensitivity may be more widespread across LOV domains than previously appreciated.