5C5E

Structure of KaiA dimer in complex with C-terminal KaiC peptide at 2.8 A resolution

Summary for 5C5E

• Entry DOI: 10.2210/pdb5c5e/pdb
• Descriptor: Circadian clock protein KaiA, KaiC C-terminal peptide, 2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)-5-[(sulfanylcarbonyl)amino]benzoic acid, ... (4 entities in total)
• Functional Keywords: clock protein kaia-kaic complex, transcription
• Biological source: Synechococcus elongatus (strain PCC 7942); More
• Total number of polymer chains: 4
• Total formula weight: 72299.85

Authors

Pattanayek, R.,Egli, M. (deposition date: 2015-06-19, release date: 2015-08-05, Last modification date: 2023-09-27)

Primary citation

Pattanayek, R.,Egli, M.
Protein-Protein Interactions in the Cyanobacterial Circadian Clock: Structure of KaiA Dimer in Complex with C-Terminal KaiC Peptides at 2.8 angstrom Resolution.
Biochemistry, 54:4575-4578, 2015

PubMed Abstract: In the cyanobacterial circadian clock, the KaiA, -B, and -C proteins with ATP constitute a post-translational oscillator. KaiA stimulates the KaiC autokinase, and KaiB antagonizes KaiA action. KaiA contacts the intrinsically disordered C-terminal regions of KaiC hexamer to promote phosphorylation across subunit interfaces. The crystal structure of KaiA dimer from Synechococcus elongatus with two KaiC C-terminal 20mer peptides bound reveals that the latter adopt an α-helical conformation and contact KaiA α-helical bundles via mostly hydrophobic interactions. This complex and the crystal structure of KaiC hexamer with truncated C-terminal tails can be fit into the electron microscopy (EM) density of the KaiA:KaiC complex. The hybrid model helps rationalize clock phenotypes of KaiA and KaiC mutants.

PubMed: 26200123
DOI: 10.1021/acs.biochem.5b00694

Experimental method

X-RAY DIFFRACTION (2.82 Å)