8WVE

Crystal Structure of Cyanobacterial Circadian Clock Protein KaiC

8WVE の概要

• エントリーDOI: 10.2210/pdb8wve/pdb
• 関連するPDBエントリー: 8WV8
• 分子名称: Circadian clock oscillator protein KaiC, ADENOSINE-5'-TRIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• 機能のキーワード: clock protein, transferase
• 由来する生物種: Synechococcus elongatus
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 118295.58

構造登録者

Furuike, Y.,Akiyama, S. (登録日: 2023-10-23, 公開日: 2023-12-27, 最終更新日: 2024-06-12)

主引用文献

Furuike, Y.,Yamashita, E.,Akiyama, S.
Structure-function relationship of KaiC around dawn.
Biophys Physicobio., 21:e210001-e210001, 2024

PubMed Abstract: KaiC is a multifunctional enzyme functioning as the core of the circadian clock system in cyanobacteria: its N-terminal domain has adenosine triphosphatase (ATPase) activity, and its C-terminal domain has autokinase and autophosphatase activities targeting own S431 and T432. The coordination of these multiple biochemical activities is the molecular basis for robust circadian rhythmicity. Therefore, much effort has been devoted to elucidating the cooperative relationship between the two domains. However, structural and functional relationships between the two domains remain unclear especially with respect to the dawn phase, at which KaiC relieves its nocturnal history through autodephosphorylation. In this study, we attempted to design a double mutation of S431 and T432 that can capture KaiC as a fully dephosphorylated form with minimal impacts on its structure and function, and investigated the cooperative relationship between the two domains in the night to morning phases from many perspectives. The results revealed that both domains cooperate at the dawn phase through salt bridges formed between the domains, thereby non-locally co-activating two events, ATPase de-inhibition and S431 dephosphorylation. Our further analysis using existing crystal structures of KaiC suggests that the states of both domains are not always in one-to-one correspondence at every phase of the circadian cycle, and their coupling is affected by the interactions with KaiA or adjacent subunits within a KaiC hexamer.

PubMed: 38803331
DOI: 10.2142/biophysico.bppb-v21.0001

実験手法

X-RAY DIFFRACTION (2.729 Å)