4G86

Crystal structure of the redox-active cofactor DBMIB bound to the full length circadian clock protein KaiA from Synechococcus elongatus

Summary for 4G86

• Entry DOI: 10.2210/pdb4g86/pdb
• Related: 1R8J
• Descriptor: Circadian clock protein kaiA, 2,5-DIBROMO-3-ISOPROPYL-6-METHYLBENZO-1,4-QUINONE, PENTAETHYLENE GLYCOL, ... (6 entities in total)
• Functional Keywords: homodimer, kaic phosphorylation activator, kaic, protein binding
• Biological source: Synechococcus elongatus
• Total number of polymer chains: 2
• Total formula weight: 67393.20

Authors

Pattanayek, R.,Egli, M. (deposition date: 2012-07-21, release date: 2012-10-24, Last modification date: 2024-02-28)

Primary citation

Pattanayek, R.,Sidiqi, S.K.,Egli, M.
Crystal Structure of the Redox-Active Cofactor Dibromothymoquinone Bound to Circadian Clock Protein KaiA and Structural Basis for Dibromothymoquinone's Ability to Prevent Stimulation of KaiC Phosphorylation by KaiA.
Biochemistry, 51:8050-8052, 2012

PubMed Abstract: KaiA protein that stimulates KaiC phosphorylation in the cyanobacterial circadian clock was recently shown to be destabilized by dibromothymoquinone (DBMIB), thus revealing KaiA as a sensor of the plastoquinone (PQ) redox state and suggesting an indirect control of the clock by light through PQ redox changes. Here we show using X-ray crystallography that several DBMIBs are bound to KaiA dimer. Some binding modes are consistent with oligomerization of N-terminal KaiA pseudoreceiver domains and/or reduced interdomain flexibility. DBMIB bound to the C-terminal KaiA (C-KaiA) domain and limited stimulation of KaiC kinase activity by C-KaiA in the presence of DBMIB demonstrate that the cofactor may weakly inhibit KaiA-KaiC binding.

PubMed: 23020633
DOI: 10.1021/bi301222t

Experimental method

X-RAY DIFFRACTION (2.387 Å)