Circadian clocks evolved in diverse organisms as an adaptation to the daily swings in ambient light and temperature that derive from Earth’s rotation. These timing systems, based on intracellular molecular oscillations, synchronize organisms' behavior and physiology with the 24-h environmental rhythm. The cyanobacterial clock serves as a special model for understanding circadian rhythms because it can be fully reconstituted . This review summarizes recent advances that leverage new biochemical, biophysical, and mathematical approaches to shed light on the molecular mechanisms of cyanobacterial Kai proteins that support the clock, and their homologues in other bacteria. Many questions remain in circadian biology, and the tools developed for the Kai system will bring us closer to the answers.

中文翻译：

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古代生物钟的内部运作

生物钟在不同的生物体中进化，以适应因地球自转而产生的环境光和温度的日常波动。这些计时系统基于细胞内分子振荡，使生物体的行为和生理与 24 小时环境节律同步。蓝藻生物钟可以作为理解昼夜节律的特殊模型，因为它可以完全重建。这篇综述总结了利用新的生化、生物物理和数学方法来阐明支持时钟的蓝藻 Kai 蛋白及其在其他细菌中的同源物的分子机制的最新进展。昼夜节律生物学仍然存在许多问题，为 Kai 系统开发的工具将使我们更接近答案。