8UQK

Pfr state of photosensory core module of Stigmatella aurantiaca bacteriophytochrome 2

Summary for 8UQK

• Entry DOI: 10.2210/pdb8uqk/pdb
• EMDB information: 42472
• Descriptor: Bacteriophytochrome (Light-regulated signal transduction histidine kinase) (1 entity in total)
• Functional Keywords: red light photoreceptor, two component system, signaling protein
• Biological source: Stigmatella aurantiaca
• Total number of polymer chains: 2
• Total formula weight: 162301.52

Authors

Malla, T.N.,Schmidt, M.,Stojkovic, E.A. (deposition date: 2023-10-23, release date: 2024-09-25)

Primary citation

Malla, T.N.,Hernandez, C.,Muniyappan, S.,Menendez, D.,Bizhga, D.,Mendez, J.H.,Schwander, P.,Stojkovic, E.A.,Schmidt, M.
Photoreception and signaling in bacterial phytochrome revealed by single-particle cryo-EM.
Sci Adv, 10:eadq0653-eadq0653, 2024

PubMed Abstract: Phytochromes are red-light photoreceptors discovered in plants with homologs in bacteria and fungi that regulate a variety of physiological responses. They display a reversible photocycle between two distinct states: a red-light-absorbing Pr state and a far-red light-absorbing Pfr state. The photoconversion regulates the activity of an enzymatic domain, usually a histidine kinase (HK). The molecular mechanism that explains how light controls the HK activity is not understood because structures of unmodified bacterial phytochromes with HK activity are missing. Here, we report three cryo-electron microscopy structures of a wild-type bacterial phytochrome with HK activity determined as Pr and Pfr homodimers and as a Pr/Pfr heterodimer with individual subunits in distinct states. We propose that the Pr/Pfr heterodimer is a physiologically relevant signal transduction intermediate. Our results offer insight into the molecular mechanism that controls the enzymatic activity of the HK as part of a bacterial two-component system that perceives and transduces light signals.

PubMed: 39121216
DOI: 10.1126/sciadv.adq0653

Experimental method

ELECTRON MICROSCOPY (4.61 Å)