7RZW

CryoEM structure of Arabidopsis thaliana phytochrome B

7RZW の概要

• エントリーDOI: 10.2210/pdb7rzw/pdb
• EMDBエントリー: 24780
• 分子名称: Phytochrome B, 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)
• 機能のキーワード: phytochrome, asymmetric dimer, gene regulation
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 260119.45

構造登録者

Li, H.,Burgie, E.S.,Vierstra, R.D.,Li, H. (登録日: 2021-08-27, 公開日: 2022-04-13, 最終更新日: 2022-04-20)

主引用文献

Li, H.,Burgie, E.S.,Gannam, Z.T.K.,Li, H.,Vierstra, R.D.
Plant phytochrome B is an asymmetric dimer with unique signalling potential.
Nature, 604:127-133, 2022

PubMed Abstract: Many aspects of plant photoperception are mediated by the phytochrome (Phy) family of bilin-containing photoreceptors that reversibly interconvert between inactive Pr and active Pfr conformers. Despite extensive biochemical studies, full understanding of plant Phy signalling has remained unclear due to the absence of relevant 3D models. Here we report a cryo-electron microscopy structure of Arabidopsis PhyB in the Pr state that reveals a topologically complex dimeric organization that is substantially distinct from its prokaryotic relatives. Instead of an anticipated parallel architecture, the C-terminal histidine-kinase-related domains (HKRDs) associate head-to-head, whereas the N-terminal photosensory regions associate head-to-tail to form a parallelogram-shaped platform with near two-fold symmetry. The platform is internally linked by the second of two internal Per/Arnt/Sim domains that binds to the photosensory module of the opposing protomer and a preceding 'modulator' loop that assembles tightly with the photosensory module of its own protomer. Both connections accelerate the thermal reversion of Pfr back to Pr, consistent with an inverse relationship between dimer assembly and Pfr stability. Lopsided contacts between the HKRDs and the platform create profound asymmetry to PhyB that might imbue distinct signalling potentials to the protomers. We propose that this unique structural dynamism creates an extensive photostate-sensitive surface for conformation-dependent interactions between plant Phy photoreceptors and their signalling partners.

PubMed: 35355010
DOI: 10.1038/s41586-022-04529-z

実験手法

ELECTRON MICROSCOPY (3.3 Å)