The primary structural photoresponse of phytochrome proteins captured by a femtosecond X-ray laser
Category
Published on
Type
journal-article
Author
Elin Claesson and Weixiao Yuan Wahlgren and Heikki Takala and Suraj Pandey and Leticia Castillon and Valentyna Kuznetsova and Léocadie Henry and Matthijs Panman and Melissa Carrillo and Joachim Kübel and Rahul Nanekar and Linnéa Isaksson and Amke Nimmrich and Andrea Cellini and Dmitry Morozov and Michał Maj and Moona Kurttila and Robert Bosman and Eriko Nango and Rie Tanaka and Tomoyuki Tanaka and Luo Fangjia and So Iwata and Shigeki Owada and Keith Moffat and Gerrit Groenhof and Emina A. Stojković and Janne A. Ihalainen and Marius Schmidt and Sebastian Westenhoff
Citation
Claesson, E. et al., 2020. The primary structural photoresponse of phytochrome proteins captured by a femtosecond X-ray laser. eLife, 9. Available at: http://dx.doi.org/10.7554/elife.53514.
Abstract
Phytochrome proteins control the growth, reproduction, and photosynthesis of plants, fungi, and bacteria. Light is detected by a bilin cofactor, but it remains elusive how this leads to activation of the protein through structural changes. We present serial femtosecond X-ray crystallographic data of the chromophore-binding domains of a bacterial phytochrome at delay times of 1 ps and 10 ps after photoexcitation. The data reveal a twist of the D-ring, which leads to partial detachment of the chromophore from the protein. Unexpectedly, the conserved so-called pyrrole water is photodissociated from the chromophore, concomitant with movement of the A-ring and a key signalling aspartate. The changes are wired together by ultrafast backbone and water movements around the chromophore, channeling them into signal transduction towards the output domains. We suggest that the observed collective changes are important for the phytochrome photoresponse, explaining the earliest steps of how plants, fungi and bacteria sense red light.
DOI
Funding
NSF-STC Biology with X-ray Lasers (NSF-1231306)