Circadian rhythmicity by autocatalysis.

Mehra, Arun; Hong, Christian I; Shi, Mi; Loros, Jennifer J; Dunlap, Jay C; Ruoff, Peter · PLoS Comput Biol · 2006

basic_science · Level V

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Abstract

The temperature compensated in vitro oscillation of cyanobacterial KaiC phosphorylation, the first example of a thermodynamically closed system showing circadian rhythmicity, only involves the three Kai proteins (KaiA, KaiB, and KaiC) and ATP. In this paper, we describe a model in which the KaiA- and KaiB-assisted autocatalytic phosphorylation and dephosphorylation of KaiC are the source for circadian rhythmicity. This model, based upon autocatalysis instead of transcription-translation negative feedback, shows temperature-compensated circadian limit-cycle oscillations with KaiC phosphorylation profiles and has period lengths and rate constant values that are consistent with experimental observations.

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