Emberly Eldon, Wingreen Ned S
Physics Department, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
Phys Rev Lett. 2006 Jan 27;96(3):038303. doi: 10.1103/PhysRevLett.96.038303. Epub 2006 Jan 24.
Many organisms possess internal biochemical clocks, known as circadian oscillators, which allow them to regulate their biological activity with a 24-hour period. It was recently discovered that the circadian oscillator of photosynthetic cyanobacteria is able to function in a test tube with only three proteins, KaiA, KaiB, and KaiC, and ATP. Biochemical events are intrinsically stochastic, and this tends to desynchronize oscillating protein populations. We propose that stability of the Kai-protein oscillator relies on active synchronization by (i) monomer exchange between KaiC hexamers during the day, and (ii) formation of clusters of KaiC hexamers at night. Our results highlight the importance of collective assembly or disassembly of proteins in biochemical networks, and may help guide design of novel protein-based oscillators.
许多生物体拥有内部生化时钟，即昼夜节律振荡器，这使它们能够以24小时为周期调节其生物活性。最近发现，光合蓝细菌的昼夜节律振荡器仅在含有三种蛋白质（KaiA、KaiB和KaiC）以及ATP的试管中就能发挥作用。生化事件本质上是随机的，这往往会使振荡的蛋白质群体失去同步。我们提出，Kai蛋白振荡器的稳定性依赖于以下主动同步机制：（i）白天KaiC六聚体之间的单体交换，以及（ii）夜间KaiC六聚体聚集体的形成。我们的结果突出了生化网络中蛋白质集体组装或拆卸的重要性，并可能有助于指导新型基于蛋白质的振荡器的设计。
