Malla Tek Narsingh, Aldama Luis, Leon Viridiana, Feliz Denisse, Hu Hao, Thomas Isaiah, Cellini Andrea, Wahlgren Weixiao Y, Nimmrich Amke, Botha Sabine, Sierra Ray, Hunter Mark S, Poitevin Frédéric, Lisova Stella, Batyuk Alexander, Gate Gregory, Jernigan Rebecca, Kupitz Christopher J, Maj Piotr, Meszaros Petra, Kurttila Moona, Monrroy Leonardo, Luo Fangjia, Owada Shigeki, Kang Jungmin, Slavov Chavdar, Maj Michal, Gautier Candice, Kashipathy Maithri, Tolstikova Alexandra, Mariani Valerio, Barty Anton, Moss Frank, Schwander Peter, Liu Haiguang, Boutet Sébastien, Fromme Petra, Takala Heikki, Ihalainen Janne A, Weierstall Uwe, Westenhoff Sebastian, Stojković Emina A, Schmidt Marius
Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
Vaccine Research Center Electron Microscopy Unit, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
Commun Chem. 2025 Jun 12;8(1):183. doi: 10.1038/s42004-025-01578-z.
Myxobacteria are non-photosynthetic, soil-dwelling bacteria distinguished by a multicellular stage in their life cycle known as fruiting bodies that are stimulated by light. Myxobacterial phytochromes are candidates for the perception of red-light. The mechanism how light is perceived and converted to a physiological response is unknown. Here, time-resolved serial femtosecond crystallographic (TR-SFX) experiments were conducted on microcrystals of the photosensory core module of the Stigmatella aurantiaca bacteriophytochrome 2 (SaBphP2). Initial events of the Z to E isomerization reaction of the covalently bound, open-chain tetrapyrrole biliverdin (BV) chromophore were determined. At 3 ps after light activation, the BV ring-D assumes a configuration needed for the isomerization. At 100 ps, a mixture of BV in the Z or E configuration is observed in subunit A, while in the other subunit the chromophore remains in the Z configuration. In conjunction with prior results, these structures reveal the molecular mechanism of phytochrome activation in the photomorphogenesis of the myxobacteria and provide the molecular foundation for physiological responses to red light in other bacteria.
黏细菌是一类非光合的土壤细菌，其生命周期中的多细胞阶段以受光刺激的子实体为特征。黏细菌的光敏色素是感知红光的候选物质。光如何被感知并转化为生理反应的机制尚不清楚。在此，对橙色标桩菌细菌光敏色素2（SaBphP2）的光感核心模块微晶进行了时间分辨串联飞秒晶体学（TR-SFX）实验。确定了共价结合的开链四吡咯胆绿素（BV）发色团从Z型到E型异构化反应的初始事件。光激活后3皮秒，BV环-D呈现异构化所需的构型。在100皮秒时，在亚基A中观察到Z型或E型BV的混合物，而在另一个亚基中，发色团保持Z型构型。结合先前的结果，这些结构揭示了黏细菌光形态建成中光敏色素激活的分子机制，并为其他细菌对红光的生理反应提供了分子基础。
