1e6l
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(New page: 200px<br /><applet load="1e6l" size="450" color="white" frame="true" align="right" spinBox="true" caption="1e6l, resolution 1.9Å" /> '''TWO-COMPONENT SIGNAL ...)
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Revision as of 11:41, 20 November 2007
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TWO-COMPONENT SIGNAL TRANSDUCTION SYSTEM D13A MUTANT OF CHEY
Overview
The signal transduction protein CheY displays an alpha/beta-parallel, polypeptide folding, including a highly unstable helix alpha4 and a, strongly charged active site. Helix alpha4 has been shown to adopt various, positions and conformations in different crystal structures, suggesting, that it is a mobile segment. Furthermore, the instability of this helix is, believed to have functional significance because it is involved in, protein-protein contacts with the transmitter protein kinase CheA, the, target protein FliM and the phosphatase CheZ. The active site of CheY, comprises a cluster of three aspartic acid residues and a lysine residue, all of which participate in the binding of the Mg(2+) needed for the, protein activation. Two steps were followed to study the activation, mechanism of CheY upon phosphorylation: first, we independently, substituted the three aspartic acid residues in the active site with, alanine; second, several mutations were designed in helix alpha 4, both to, increase its level of stability and to improve its packing against the, protein core. The structural and thermodynamic analysis of these mutant, proteins provides further evidence of the connection between the, active-site area and helix alpha 4, and helps to understand how small, movements at the active site are transmitted and amplified to the protein, surface.
About this Structure
1E6L is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Towards understanding a molecular switch mechanism: thermodynamic and crystallographic studies of the signal transduction protein CheY., Sola M, Lopez-Hernandez E, Cronet P, Lacroix E, Serrano L, Coll M, Parraga A, J Mol Biol. 2000 Oct 20;303(2):213-25. PMID:11023787
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