It is essential for many organisms to be able to respond to light. Biological systems use photoreceptor proteins to detect light through molecules known as chromophores. The bacterial photoreceptor CarH uses a vitamin B 12 derivative called adenosylcobalamin (AdoCbl) as a chromophore, co-opting it from its normal function as a cofactor for enzymatic reactions1,2. Writing in Nature, a collaboration of several international teams of scientists (Rios-Santacruz et al.3) report that they have used cutting-edge structural-biology methods to capture snapshots of CarH in action, thereby revealing what happens to AdoCbl as soon as 10 nanoseconds after exposure to light. The findings answer a long-standing question about how CarH controls the light-induced breakdown of AdoCbl.
doi: https://doi.org/10.1038/d41586-026-00169-9
References Padmanabhan, S., Jost, M., Drennan, C. L. & Elías-Arnanz, M. Annu. Rev. Biochem. 86, 485–514 (2017). Ortiz-Guerrero, J. M., Polanco, M. C., Murillo, F. J., Padmanabhan, S. & Elías-Arnanz, M. Proc. Natl Acad. Sci. USA 108, 7565–7570 (2011). Rios-Santacruz, R. et al. Nature https://doi.org/10.1038/s41586-025-10074-2 (2026). Jost, M. et al. Nature 526, 536–541 (2015). Bridwell-Rabb, J. & Drennan, C. L. Curr. Opin. Chem. Biol. 37, 63–70 (2017). Jost, M., Simpson, J. H. & Drennan, C. L. Biochemistry 54, 3231–3234 (2015). Poddar, H. et al. FEBS J. 289, 576–595 (2022). Weik, M. & Domratcheva, T. Curr. Opin. Struct. Biol. 77, 102496 (2022). Lee, Y-H. et al. J. Am. Chem. Soc. 147, 25224–25232 (2025). Avalos, D. M. & Drennan, C. L. J. Inorg. Biochem. 277, 113204 (2026). Download references
Competing Interests The authors declare no competing interests.
Related Articles
Subjects