- EMDB-29506: Structure of dodecameric KaiC-RS-S413E/S414E complexed with KaiB-... -
+
データを開く
IDまたはキーワード:
読み込み中...
-
基本情報
登録情報
データベース: EMDB / ID: EMD-29506
タイトル
Structure of dodecameric KaiC-RS-S413E/S414E complexed with KaiB-RS solved by cryo-EM
マップデータ
Composite map of two hexamer reconstructions aligned and combined by taking the maximum absolute value
試料
複合体: Dodecamer of KaiC-RS-S413E/S414E bound with KaiC-RS
タンパク質・ペプチド: Circadian clock protein KaiC
タンパク質・ペプチド: Circadian clock protein KaiB
リガンド: ADENOSINE-5'-TRIPHOSPHATE
リガンド: ADENOSINE-5'-DIPHOSPHATE
リガンド: MAGNESIUM ION
リガンド: water
キーワード
autokinase / CIRCADIAN CLOCK PROTEIN
機能・相同性
機能・相同性情報
rhythmic process / kinase activity / non-specific serine/threonine protein kinase / phosphorylation / ATP hydrolysis activity / ATP binding / metal ion binding 類似検索 - 分子機能
ジャーナル: Nature / 年: 2023 タイトル: From primordial clocks to circadian oscillators. 著者: Warintra Pitsawong / Ricardo A P Pádua / Timothy Grant / Marc Hoemberger / Renee Otten / Niels Bradshaw / Nikolaus Grigorieff / Dorothee Kern / 要旨: Circadian rhythms play an essential part in many biological processes, and only three prokaryotic proteins are required to constitute a true post-translational circadian oscillator. The evolutionary ...Circadian rhythms play an essential part in many biological processes, and only three prokaryotic proteins are required to constitute a true post-translational circadian oscillator. The evolutionary history of the three Kai proteins indicates that KaiC is the oldest member and a central component of the clock. Subsequent additions of KaiB and KaiA regulate the phosphorylation state of KaiC for time synchronization. The canonical KaiABC system in cyanobacteria is well understood, but little is known about more ancient systems that only possess KaiBC. However, there are reports that they might exhibit a basic, hourglass-like timekeeping mechanism. Here we investigate the primordial circadian clock in Rhodobacter sphaeroides, which contains only KaiBC, to elucidate its inner workings despite missing KaiA. Using a combination of X-ray crystallography and cryogenic electron microscopy, we find a new dodecameric fold for KaiC, in which two hexamers are held together by a coiled-coil bundle of 12 helices. This interaction is formed by the carboxy-terminal extension of KaiC and serves as an ancient regulatory moiety that is later superseded by KaiA. A coiled-coil register shift between daytime and night-time conformations is connected to phosphorylation sites through a long-range allosteric network that spans over 140 Å. Our kinetic data identify the difference in the ATP-to-ADP ratio between day and night as the environmental cue that drives the clock. They also unravel mechanistic details that shed light on the evolution of self-sustained oscillators.