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Literature DB >> 15003530

Stoichiometric interactions between cyanobacterial clock proteins KaiA and KaiC.

Fumio Hayashi¹, Hiroki Ito, Masayasu Fujita, Ryo Iwase, Tatsuya Uzumaki, Masahiro Ishiura.

Abstract

We determined the stoichiometry of KaiA-KaiC interactions. Using immunoblotting and two-dimensional Native- and SDS-PAGE (2DNS-PAGE) analysis, we demonstrated that the reaction products of KaiA-KaiC interactions in the presence of ATP consisted of only phosphorylated KaiC whereas in the presence of the unhydrolyzable analogue 5'-adenylylimidodiphosphate (AMPPNP) they consisted of KaiA and KaiC. In the presence of ATP, the KE (molar ratio of KaiA dimer to KaiC hexamer giving half saturation in the enhancement of KaiC phosphorylation) was 0.25, and IAsys affinity biosensor analysis demonstrated that 1 molecule of KaiA dimer interacted with 1 molecule of KaiC hexamer. In the presence of AMPPNP, the ratio of KaiA dimer to KaiC hexamer in KaiA-KaiC complexes was determined to be 2 by 2DNS-PAGE, Native-PAGE/Scatchard plot, and IAsys analyses. These results suggest that 2 molecules of KaiA dimer can interact with 1 molecule of KaiC hexamer, and that interactions of at least 1 molecule of KaiA dimer with 1 molecule of KaiC hexamer are enough to enhance the phosphorylation of KaiC by KaiA at an almost saturated level.

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Year: 2004 PMID： 15003530 DOI： 10.1016/j.bbrc.2004.02.034

Source DB: PubMed Journal: Biochem Biophys Res Commun ISSN： 0006-291X Impact factor: 3.575

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Cited

24 in total

1. Structure of the C-terminal domain of the clock protein KaiA in complex with a KaiC-derived peptide: implications for KaiC regulation.

Authors: Ioannis Vakonakis; Andy C LiWang
Journal: Proc Natl Acad Sci U S A Date: 2004-07-15 Impact factor: 11.205

2. The roles of the dimeric and tetrameric structures of the clock protein KaiB in the generation of circadian oscillations in cyanobacteria.

Authors: Reiko Murakami; Risa Mutoh; Ryo Iwase; Yukio Furukawa; Katsumi Imada; Kiyoshi Onai; Megumi Morishita; So Yasui; Kentaro Ishii; Jonathan Orville Valencia Swain; Tatsuya Uzumaki; Keiichi Namba; Masahiro Ishiura
Journal: J Biol Chem Date: 2012-06-21 Impact factor: 5.157

10. Molecular dynamics simulations of nucleotide release from the circadian clock protein KaiC reveal atomic-resolution functional insights.

Authors: Lu Hong; Bodhi P Vani; Erik H Thiede; Michael J Rust; Aaron R Dinner
Journal: Proc Natl Acad Sci U S A Date: 2018-11-15 Impact factor: 11.205

Stoichiometric interactions between cyanobacterial clock proteins KaiA and KaiC.

1. Structure of the C-terminal domain of the clock protein KaiA in complex with a KaiC-derived peptide: implications for KaiC regulation.

2. The roles of the dimeric and tetrameric structures of the clock protein KaiB in the generation of circadian oscillations in cyanobacteria.

3. Intermolecular associations determine the dynamics of the circadian KaiABC oscillator.

4. Analysis of KaiA-KaiC protein interactions in the cyano-bacterial circadian clock using hybrid structural methods.

5. Hourglass model for a protein-based circadian oscillator.

6. An allosteric model of circadian KaiC phosphorylation.

7. The day/night switch in KaiC, a central oscillator component of the circadian clock of cyanobacteria.

8. Structural model of the circadian clock KaiB-KaiC complex and mechanism for modulation of KaiC phosphorylation.

9. Flexibility of the C-terminal, or CII, ring of KaiC governs the rhythm of the circadian clock of cyanobacteria.

10. Molecular dynamics simulations of nucleotide release from the circadian clock protein KaiC reveal atomic-resolution functional insights.