1V2Z

Crystal structure of the C-terminal domain of Thermosynechococcus elongatus BP-1 KaiA

Summary for 1V2Z

• Entry DOI: 10.2210/pdb1v2z/pdb
• Descriptor: circadian clock protein KaiA homolog (2 entities in total)
• Functional Keywords: all alpha, riken structural genomics/proteomics initiative, rsgi, structural genomics, circadian clock protein
• Biological source: Thermosynechococcus elongatus
• Total number of polymer chains: 1
• Total formula weight: 13186.21

Authors

Uzumaki, T.,Fujita, M.,Nakatsu, T.,Hayashi, F.,Shibata, H.,Itoh, N.,Kato, H.,Ishiura, M.,RIKEN Structural Genomics/Proteomics Initiative (RSGI) (deposition date: 2003-10-20, release date: 2004-06-01, Last modification date: 2023-12-27)

Primary citation

Uzumaki, T.,Fujita, M.,Nakatsu, T.,Hayashi, F.,Shibata, H.,Itoh, N.,Kato, H.,Ishiura, M.
Crystal structure of the C-terminal clock-oscillator domain of the cyanobacterial KaiA protein
NAT.STRUCT.MOL.BIOL., 11:623-631, 2004

PubMed Abstract: KaiA, KaiB and KaiC constitute the circadian clock machinery in cyanobacteria, and KaiA activates kaiBC expression whereas KaiC represses it. Here we show that KaiA is composed of three functional domains, the N-terminal amplitude-amplifier domain, the central period-adjuster domain and the C-terminal clock-oscillator domain. The C-terminal domain is responsible for dimer formation, binding to KaiC, enhancing KaiC phosphorylation and generating the circadian oscillations. The X-ray crystal structure at a resolution of 1.8 A of the C-terminal clock-oscillator domain of KaiA from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 shows that residue His270, located at the center of a KaiA dimer concavity, is essential to KaiA function. KaiA binding to KaiC probably occurs via the concave surface. On the basis of the structure, we predict the structural roles of the residues that affect circadian oscillations.

PubMed: 15170179
DOI: 10.1038/nsmb781

Experimental method

X-RAY DIFFRACTION (1.8 Å)