Sci. STKE, 6 November 2007
Systems Biology Dissecting a Core Oscillator
Beverly A. Purnell
Science, AAAS, Washington, DC 20005, USA
The core circadian oscillator of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by mixing the proteins KaiA, KaiB, and KaiC, resulting in oscillations in KaiC phosphorylation. The underlying mechanism of this biochemical oscillator has been elusive. Rust et al. (see the Perspective by Poon and Ferrell) now show that phosphorylation of KaiC at two residues is cyclically ordered and that the abundance of each phosphorylated form determines the phase of the oscillator. This sequential phosphorylation of KaiC, combined with negative feedback caused by one of the phosphorylation states, is sufficient to explain stable oscillation.
Citation: B. A. Purnell, Dissecting a Core Oscillator. Sci. STKE 2007, tw407 (2007).
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