The elucidation of ATPase-mediated intramolecular feedback in KaiC

生物钟由三种生物钟蛋白组成，分别是KaiA、KaiB和KaiC。KaiC的atp酶活性决定了体内和体外的昼夜节律周期，并具有温度补偿的基本昼夜节律特征。在这项研究中，我们展示了KaiC的atp酶活性如何在大范围温度功能中保持昼夜节律周期不变。当温度从冰上跳升到45℃时，KaiC的atp酶反应瞬间升高，并很快受到分子内反馈的抑制，但失去这一时期温度补偿特性的KaiC突变体的atp酶活性不像KaiC- wt那样出现这种衰减。我们推测KaiC具有利用C2结构域atp酶活性的分子内反馈机制，使昼夜节律周期在大范围温度范围内保持恒定。

The circadian clock comprises three clock proteins named KaiA, KaiB, and KaiC. The ATPase activity of KaiC defines the period of circadian rhythms in vivo and vitro and has an essential circadian characteristic of temperature compensation. In this study, we show how the ATPase activity of KaiC keeps the period of circadian rhythms constant across broad range temperature functions. When an ATPase reaction of KaiC are initiated by a temperature jump from on-ice to 45 °C, the ATPase activity is elevated instantaneously, and soon repressed by an intramolecular feedback in itself, but nevertheless the ATPase activity in KaiC mutant that lose the characteristic of temperature compensation of the period do not show this attenuation as KaiC-WT showed. We presumed that KaiC has an intramolecular feedback mechanism using ATPase activity of C2 domain in itself, which keeps the period of circadian rhythms constant across broad range temperature.