2QKE

Wild Type Crystal Structure of Full Length Circadian Clock Protein KaiB from Thermosynechococcus elongatus BP-1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.284 
  • R-Value Work: 0.233 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

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

Pattanayek, R.Williams, D.R.Pattanayek, S.Mori, T.Johnson, C.H.Stewart, P.L.Egli, M.

(2008) Embo J. 27: 1767-1778

  • DOI: 10.1038/emboj.2008.104

  • PubMed Abstract: 
  • The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by the KaiA, KaiB and KaiC proteins in the presence of ATP. The principal clock component, KaiC, undergoes regular cycles between hyper- and hypo-phosphor ...

    The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by the KaiA, KaiB and KaiC proteins in the presence of ATP. The principal clock component, KaiC, undergoes regular cycles between hyper- and hypo-phosphorylated states with a period of ca. 24 h that is temperature compensated. KaiA enhances KaiC phosphorylation and this enhancement is antagonized by KaiB. Throughout the cycle Kai proteins interact in a dynamic manner to form complexes of different composition. We present a three-dimensional model of the S. elongatus KaiB-KaiC complex based on X-ray crystallography, negative-stain and cryo-electron microscopy, native gel electrophoresis and modelling techniques. We provide experimental evidence that KaiB dimers interact with KaiC from the same side as KaiA and for a conformational rearrangement of the C-terminal regions of KaiC subunits. The enlarged central channel and thus KaiC subunit separation in the C-terminal ring of the hexamer is consistent with KaiC subunit exchange during the dephosphorylation phase. The proposed binding mode of KaiB explains the observation of simultaneous binding of KaiA and KaiB to KaiC, and provides insight into the mechanism of KaiB's antagonism of KaiA.


    Organizational Affiliation

    Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Circadian clock protein kaiB
A, B, C, D, E, F
108Thermosynechococcus elongatus (strain BP-1)Mutation(s): 0 
Gene Names: kaiB
Find proteins for Q79V61 (Thermosynechococcus elongatus (strain BP-1))
Go to UniProtKB:  Q79V61
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.284 
  • R-Value Work: 0.233 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 100.132α = 90.00
b = 191.218β = 90.00
c = 34.339γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data scaling
CNSphasing
HKL-2000data collection
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-06-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance