1r8j
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(New page: 200px<br /><applet load="1r8j" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r8j, resolution 2.03Å" /> '''Crystal Structure of...)
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Revision as of 23:14, 20 November 2007
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Crystal Structure of Circadian Clock Protein KaiA from Synechococcus elongatus
Overview
The circadian clock found in Synechococcus elongatus, the most ancient, circadian clock, is regulated by the interaction of three proteins, KaiA, KaiB, and KaiC. While the precise function of these proteins remains, unclear, KaiA has been shown to be a positive regulator of the expression, of KaiB and KaiC. The 2.0-A structure of KaiA of S. elongatus reported, here shows that the protein is composed of two independently folded, domains connected by a linker. The NH(2)-terminal pseudo-receiver domain, has a similar fold with that of bacterial response regulators, whereas the, COOH-terminal four-helix bundle domain is novel and forms the interface of, the 2-fold-related homodimer. The COOH-terminal four-helix bundle domain, has been shown to contain the KaiC binding site. The structure suggests, that the KaiB binding site is covered in the dimer interface of the KaiA, "closed" conformation, observed in the crystal structure, which suggests, an allosteric regulation mechanism.
About this Structure
1R8J is a Single protein structure of sequence from Synechococcus elongatus. Full crystallographic information is available from OCA.
Reference
Crystal structure of circadian clock protein KaiA from Synechococcus elongatus., Ye S, Vakonakis I, Ioerger TR, LiWang AC, Sacchettini JC, J Biol Chem. 2004 May 7;279(19):20511-8. Epub 2004 Mar 8. PMID:15007067
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