1u9i
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1u9i.gif|left|200px]] | [[Image:1u9i.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1u9i", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1u9i| PDB=1u9i | SCENE= }} | |
| - | + | ||
| - | | | + | |
| - | }} | + | |
'''Crystal Structure of Circadian Clock Protein KaiC with Phosphorylation Sites''' | '''Crystal Structure of Circadian Clock Protein KaiC with Phosphorylation Sites''' | ||
| Line 31: | Line 28: | ||
[[Category: Pattanayek, S.]] | [[Category: Pattanayek, S.]] | ||
[[Category: Xu, Y.]] | [[Category: Xu, Y.]] | ||
| - | [[Category: | + | [[Category: Circadian]] |
| - | [[Category: | + | [[Category: Clock]] |
| - | [[Category: | + | [[Category: Hexamer]] |
| - | [[Category: | + | [[Category: Homohexamer]] |
| - | [[Category: | + | [[Category: Kaia]] |
| - | [[Category: | + | [[Category: Kaib]] |
| - | [[Category: | + | [[Category: Kaic]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 10:55:53 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 07:55, 3 May 2008
Crystal Structure of Circadian Clock Protein KaiC with Phosphorylation Sites
Overview
In cyanobacteria, KaiC is an essential hexameric clock protein that forms the core of a circadian protein complex. KaiC can be phosphorylated, and the ratio of phospho-KaiC to non-phospho-KaiC is correlated with circadian period. Structural analyses of KaiC crystals identify three potential phosphorylation sites within a 10-A radius of the ATP binding regions that are at the T432, S431, and T426 residues in the KaiCII domains. When these residues are mutated by alanine substitution singly or in combination, KaiC phosphorylation is altered, and circadian rhythmicity is abolished. These alanine substitutions do not prevent KaiC from hexamerizing. Intriguingly, the ability of KaiC overexpression to repress its own promoter is also not prevented by alanine substitutions at these sites, implying that the capability of KaiC to repress its promoter is not sufficient to allow the clockwork to oscillate. The KaiC structure and the mutational analysis suggest that S431 and T426 may share a phosphate that can shuttle between these two residues. Because the phosphorylation status of KaiC oscillates over the daily cycle, and KaiC phosphorylation is essential for clock function as shown here, daily modulations of KaiC activity by phosphorylation at T432 and S431/T426 seem to be key components of the circadian clockwork in cyanobacteria.
About this Structure
1U9I is a Protein complex structure of sequences from Synechococcus sp.. Full crystallographic information is available from OCA.
Reference
Identification of key phosphorylation sites in the circadian clock protein KaiC by crystallographic and mutagenetic analyses., Xu Y, Mori T, Pattanayek R, Pattanayek S, Egli M, Johnson CH, Proc Natl Acad Sci U S A. 2004 Sep 21;101(38):13933-8. Epub 2004 Sep 3. PMID:15347809 Page seeded by OCA on Sat May 3 10:55:53 2008
Categories: Protein complex | Synechococcus sp. | Egli, M. | Johnson, C H. | Mori, T. | Pattanayek, R. | Pattanayek, S. | Xu, Y. | Circadian | Clock | Hexamer | Homohexamer | Kaia | Kaib | Kaic
