8F5Z

Composite map of CryoEM structure of Arabidopsis thaliana phytochrome A

Summary for 8F5Z

• Entry DOI: 10.2210/pdb8f5z/pdb
• EMDB information: 28869 28870 28871 28872
• Descriptor: Phytochrome A, 3-[5-[[(3~{R},4~{R})-3-ethyl-4-methyl-5-oxidanylidene-3,4-dihydropyrrol-2-yl]methyl]-2-[[5-[(4-ethyl-3-methyl-5-oxidanylidene-pyrrol-2-yl)methyl]-3-(3-hydroxy-3-oxopropyl)-4-methyl-1~{H}-pyrrol-2-yl]methyl]-4-methyl-1~{H}-pyrrol-3-yl]propanoic acid (2 entities in total)
• Functional Keywords: phytochrome, asymmetric dimer, gene regulation
• Biological source: Arabidopsis thaliana (thale cress)
• Total number of polymer chains: 2
• Total formula weight: 250593.00

Authors

Li, H.,Li, H. (deposition date: 2022-11-15, release date: 2023-06-28, Last modification date: 2024-10-23)

Primary citation

Burgie, E.S.,Li, H.,Gannam, Z.T.K.,McLoughlin, K.E.,Vierstra, R.D.,Li, H.
The structure of Arabidopsis phytochrome A reveals topological and functional diversification among the plant photoreceptor isoforms.
Nat.Plants, 9:1116-1129, 2023

PubMed Abstract: Plants employ a divergent cohort of phytochrome (Phy) photoreceptors to govern many aspects of morphogenesis through reversible photointerconversion between inactive Pr and active Pfr conformers. The two most influential are PhyA whose retention of Pfr enables sensation of dim light, while the relative instability of Pfr for PhyB makes it better suited for detecting full sun and temperature. To better understand these contrasts, we solved, by cryo-electron microscopy, the three-dimensional structure of full-length PhyA as Pr. Like PhyB, PhyA dimerizes through head-to-head assembly of its C-terminal histidine kinase-related domains (HKRDs), while the remainder assembles as a head-to-tail light-responsive platform. Whereas the platform and HKRDs associate asymmetrically in PhyB dimers, these lopsided connections are absent in PhyA. Analysis of truncation and site-directed mutants revealed that this decoupling and altered platform assembly have functional consequences for Pfr stability of PhyA and highlights how plant Phy structural diversification has extended light and temperature perception.

PubMed: 37291396
DOI: 10.1038/s41477-023-01435-8

Experimental method

ELECTRON MICROSCOPY (3.2 Å)