Optical absorption spectra of a microbial rhodopsin in 400 T ultra-high magnetic fields

Magnetic field effects on biological functions are generally considered negligible, as the magnetic energy change in electronic states is typically around 0.1 meV even at 1 T. However, the recent availability of magnetic fields exceeding 1000 T provides new opportunities to explore potential magnetic influences on biomolecular processes [1]. In this study, we investigated the impact of ultra-high magnetic fields on a microbial rhodopsin, schizorhodopsin 1 (SzR1), which has been extensively studied for its photoreceptive properties [2]. Absorption spectra in the range of 450–650 nm was measured under varying magnetic field strengths. The results revealed both absorption intensity variations and spectral energy shifts correlated with increasing magnetic field strength. These observations suggest that the electronic state in SzR1 may become more sensitive to a magnetic field, which might be a sign of a crossover or a phase transition at an ultra-high magnetic field.