Solution Structure of the C-terminal Domain of Thermosynechococcus elongatus KaiA (ThKaiA180C); Averaged Minimized Structure

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Submitted: 

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NMR structure of the KaiC-interacting C-terminal domain of KaiA, a circadian clock protein: Implications for KaiA-KaiC interaction

Vakonakis, I.Sun, J.Wu, T.Holzenburg, A.Golden, S.S.LiWang, A.C.

(2004) Proc Natl Acad Sci U S A 101: 1479-1484

  • DOI: https://doi.org/10.1073/pnas.0305516101
  • Primary Citation of Related Structures:  
    1Q6A, 1Q6B

  • PubMed Abstract: 

    KaiA is a two-domain circadian clock protein in cyanobacteria, acting as the positive element in a feedback loop that sustains the oscillation. The structure of the N-terminal domain of KaiA is that of a pseudo-receiver, similar to those of bacterial response regulators, which likely interacts with components of the clock-resetting pathway. The C-terminal domain of KaiA is highly conserved among cyanobacteria and enhances the autokinase activity of KaiC. Here we present the NMR structure of the C-terminal domain of KaiA from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1. This domain adopts a novel all alpha-helical homodimeric structure. Several mutations known to affect the period of the circadian oscillator are shown to be located at an exposed groove near the dimer interface. This NMR structure and a 21-A-resolution electron microscopy structure of the hexameric KaiC particle allow us to postulate a mode of KaiA-KaiC interaction, in which KaiA binds a linker region connecting two globular KaiC domains.

  • Organizational Affiliation

    Departments of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Circadian clock protein KaiA homolog
A, B
107Thermosynechococcus vestitus BP-1Mutation(s): 0 
Gene Names: KaiA
Find proteins for Q79V62 (Thermosynechococcus vestitus (strain NIES-2133 / IAM M-273 / BP-1))
Explore Q79V62 
Go to UniProtKB:  Q79V62
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ79V62
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Submitted: 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-08-19
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance