title: A circadian clock nanomachine that runs without transcription or translation.
abstract: The biochemical basis of circadian timekeeping is best characterized in cyanobacteria. The structures of its key molecular players, KaiA, KaiB, and KaiC are known and these proteins can reconstitute a remarkable circadian oscillation in a test tube. KaiC is rhythmically phosphorylated and its phospho-status is a marker of circadian phase that regulates ATPase activity and the oscillating assembly of a nanomachine. Analyses of the nanomachines have revealed how their timing circuit is ratcheted to be unidirectional and how they stay in synch to ensure a robust oscillator. These insights are likely to elucidate circadian timekeeping in higher organisms, including how transcription and translation could appear to be a core circadian timer when the true pacemaker is an embedded biochemical oscillator.
authors.affiliation: Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA. Electronic address: martin.egli@vanderbilt.edu.
authors.forename: Martin
authors.initials: M
authors.lastname: Egli
authors.forename: Carl Hirschie
authors.initials: CH
authors.lastname: Johnson
mesh_terms: D000818:Animals; D018407:Bacterial Physiological Phenomena; D001426:Bacterial Proteins / Q000378:metabolism; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D000458:Cyanobacteria / Q000502:physiology*; D050997:Nanomedicine
chemical_list: D001426:Bacterial Proteins