Modulation of thermal noise and spectral sensitivity in Lake Baikal cottoid fish rhodopsins

Lake Baikal cottoid fish rhodopsins exhibit a blue-shift in spectral sensitivity with increasing depth, linked to reduced thermal noise. This adaptation enhances vision in deep-water low-light environments. Researchers combined homology modeling, quantum chemical calculations, and experimental measurements to reveal a Barlow-type relationship between absorption maxima and thermal isomerization rates. Nakanishi point-charge analysis identified amino acid residues that simultaneously modulate spectral tuning and visual sensitivity, suggesting natural variation at these sites drives both thermal noise reduction and spectral shifting.

Luk, H. L., Bhattacharyya, N., Montisci, F., Morrow, J. M., Melaccio, F., Wada, A., Sheves, M., Fanelli, F., Chang, B. S. W., & Olivucci, M. (2016). Modulation of thermal noise and spectral sensitivity in Lake Baikal cottoid fish rhodopsins. Scientific Reports, 6(1). https://doi.org/10.1038/srep38425