1M2E image
Entry Detail
PDB ID:
1M2E
Title:
Solution structure of the N-terminal domain of Synechococcus elongatus KaiA (KaiA135N); Average minimized structure.
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2002-06-23
Release Date:
2002-11-13
Method Details:
Experimental Method:
Conformers Submitted:
1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:KaiA
Chain IDs:A
Chain Length:135
Number of Molecules:1
Biological Source:Synechococcus elongatus
Ligand Molecules
Primary Citation
Structure and Function from the Circadian Clock Protein KaiA of Synechococcus elongatus: A potential Clock Input Mechanism
Proc.Natl.Acad.Sci.USA 99 15357 15362 (2002)
PMID: 12438647 DOI: 10.1073/pnas.232517099

Abstact

In the cyanobacterium Synechococcus elongatus (PCC 7942) the proteins KaiA, KaiB, and KaiC are required for circadian clock function. We deduced a circadian clock function for KaiA from a combination of biochemical and structural data. Both KaiA and its isolated carboxyl-terminal domain (KaiA180C) stimulated KaiC autophosphorylation and facilitated attenuation of KaiC autophosphorylation by KaiB. An amino-terminal domain (KaiA135N) had no function in the autophosphorylation assay. NMR structure determination showed that KaiA135N is a pseudo-receiver domain. We propose that this pseudo-receiver is a timing input-device that regulates KaiA stimulation of KaiC autophosphorylation, which in turn is essential for circadian timekeeping.

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