1R5Q
Crystal Structure Analysis of Kai A from PCC7120
Summary for 1R5Q
| Entry DOI | 10.2210/pdb1r5q/pdb |
| Descriptor | circadian oscillation regulator (2 entities in total) |
| Functional Keywords | four-helix-bundle, gene regulation |
| Biological source | Nostoc sp. |
| Total number of polymer chains | 1 |
| Total formula weight | 11978.90 |
| Authors | Garces, R.G.,Wu, N.,Gillon, W.,Pai, E.F. (deposition date: 2003-10-12, release date: 2004-05-04, Last modification date: 2024-11-13) |
| Primary citation | Garces, R.G.,Wu, N.,Gillon, W.,Pai, E.F. Anabaena circadian clock proteins KaiA and KaiB reveal a potential common binding site to their partner KaiC Embo J., 23:1688-1698, 2004 Cited by PubMed Abstract: The cyanobacterial clock proteins KaiA and KaiB are proposed as regulators of the circadian rhythm in cyanobacteria. Mutations in both proteins have been reported to alter or abolish circadian rhythmicity. Here, we present molecular models of both KaiA and KaiB from the cyanobacteria Anabaena sp PCC7120 deduced by crystal structure analysis, and we discuss how clock-changing or abolishing mutations may cause their resulting circadian phenotype. The overall fold of the KaiA monomer is that of a four-helix bundle. KaiB, on the other hand, adopts an alpha-beta meander motif. Both proteins purify and crystallize as dimers. While the folds of the two proteins are clearly different, their size and some surface features of the physiologically relevant dimers are very similar. Notably, the functionally relevant residues Arg 69 of KaiA and Arg 23 of KaiB align well in space. The apparent structural similarities suggest that KaiA and KaiB may compete for a potential common binding site on KaiC. PubMed: 15071498DOI: 10.1038/sj.emboj.7600190 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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