9YXN
Pr-Pfr heterodimer state of Stigmatella aurantiaca bacteriophytochrome 2
This is a non-PDB format compatible entry.
Summary for 9YXN
| Entry DOI | 10.2210/pdb9yxn/pdb |
| EMDB information | 73612 |
| Descriptor | Bacteriophytochrome, BILIVERDINE IX ALPHA (2 entities in total) |
| Functional Keywords | signal transduction, photoactivation, signaling protein |
| Biological source | Stigmatella aurantiaca |
| Total number of polymer chains | 2 |
| Total formula weight | 161664.67 |
| Authors | Karki, P.,Stojkovic, E.A.,Schmidt, M. (deposition date: 2025-10-27, release date: 2026-06-17, Last modification date: 2026-06-24) |
| Primary citation | Karki, P.,Budell, W.C.,Kannachel, R.,Menendez, D.,Hernandez, C.,Mendez, J.H.,Kanou, S.,Singh, M.,Slavov, C.,Schwander, P.,Malla, T.N.,Stojkovic, E.A.,Schmidt, M. A bacteriophytochrome Pr/Pfr heterodimer studied through single-particle time-resolved cryo-electron microscopy. Commun Chem, 2026 Cited by PubMed Abstract: Phytochromes are dimeric photoreceptors found in bacteria, fungi, and plants that reversibly interconvert between a red-absorbing Pr state and a far-red-absorbing Pfr state. In bacteria, phytochromes (BphPs) regulate diverse responses through a two-component signaling pathway comprising a C-terminal histidine kinase (HK) and a response regulator. A previous cryo-EM study of the wild-type BphP from Stigmatella aurantiaca (SaBphP2) revealed a stable Pr/Pfr heterodimer in which the two protomers adopt distinct Pr and Pfr conformations. Here, using the Spotiton technique, we captured the same heterodimer by illuminating SaBphP2 particles on the cryo-EM grid and vitrifying them 10 ms later. Comparison with the Pr/Pr homodimer reveals a 180° rotation of the HK domain, driven by an unwinding of the coiled-coil helices that connect the photosensory core to the enzymatic domain. The large-scale reorientations provide mechanistic insight into light-triggered signal transduction mediated by bacterial phytochromes. PubMed: 42260277DOI: 10.1038/s42004-026-02084-6 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (5.01 Å) |
Structure validation
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