7DY1

Crystal Structure of Cyanobacterial Circadian Clock Protein KaiC

Summary for 7DY1

• Entry DOI: 10.2210/pdb7dy1/pdb
• Related: 7DXQ
• Descriptor: Circadian clock protein kinase KaiC, ADENOSINE-5'-TRIPHOSPHATE, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: clock protein, transferase
• Biological source: Thermosynechococcus elongatus (strain BP-1); More
• Total number of polymer chains: 6
• Total formula weight: 352869.80

Authors

Furuike, Y.,Akiyama, S. (deposition date: 2021-01-20, release date: 2022-05-18, Last modification date: 2024-11-13)

Primary citation

Furuike, Y.,Mukaiyama, A.,Koda, S.I.,Simon, D.,Ouyang, D.,Ito-Miwa, K.,Saito, S.,Yamashita, E.,Nishiwaki-Ohkawa, T.,Terauchi, K.,Kondo, T.,Akiyama, S.
Regulation mechanisms of the dual ATPase in KaiC.
Proc.Natl.Acad.Sci.USA, 119:e2119627119-e2119627119, 2022

PubMed Abstract: KaiC is a dual adenosine triphosphatase (ATPase), with one active site in its N-terminal domain and another in its C-terminal domain, that drives the circadian clock system of cyanobacteria through sophisticated coordination of the two sites. To elucidate the coordination mechanism, we studied the contribution of the dual-ATPase activities in the ring-shaped KaiC hexamer and these structural bases for activation and inactivation. At the N-terminal active site, a lytic water molecule is sequestered between the N-terminal domains, and its reactivity to adenosine triphosphate (ATP) is controlled by the quaternary structure of the N-terminal ring. The C-terminal ATPase activity is regulated mostly by water-incorporating voids between the C-terminal domains, and the size of these voids is sensitive to phosphoryl modification of S431. The up-regulatory effect on the N-terminal ATPase activity inversely correlates with the affinity of KaiC for KaiB, a clock protein constitutes the circadian oscillator together with KaiC and KaiA, and the complete dissociation of KaiB from KaiC requires KaiA-assisted activation of the dual ATPase. Delicate interactions between the N-terminal and C-terminal rings make it possible for the components of the dual ATPase to work together, thereby driving the assembly and disassembly cycle of KaiA and KaiB.

PubMed: 35507871
DOI: 10.1073/pnas.2119627119

Experimental method

X-RAY DIFFRACTION (2.2 Å)