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Sandbox Reserved 1051

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Revision as of 12:50, 28 March 2017

This Sandbox is Reserved from 02/09/2015, through 05/31/2016 for use in the course "CH462: Biochemistry 2" taught by Geoffrey C. Hoops at the Butler University. This reservation includes Sandbox Reserved 1051 through Sandbox Reserved 1080.

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Click the edit this page tab at the top. Save the page after each step, then edit it again.
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show the Scene authoring tools, create a molecular scene, and save it. Copy the green link into the page.
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CzrA

This is a default text for your page '. Click above on edit this page' to modify. Be careful with the < and > signs.

You may include any references to papers as in: the use of JSmol in Proteopedia ^[1] or to the article describing Jmol ^[2] to the rescue.

1 Biological Function
2 Structural Overview
3 Binding of DNA
4 Zinc Binding
5 References

Biological Function

Structural Overview

CzrA functions as a dimer. The dimerize at the czr operon, repressing gene transcription. Each monomeric unit contains seen in purple and displayed in yellow. While the function of the beta sheets are not yet known, key helices regulate the binding of DNA and Zn⁺². The is the location of DNA binding and the contains the Zn⁺² binding site. As Zn⁺² binds, the alpha 4 helices are , repressing their DNA binding ability.

Binding of DNA

The have been found to be the SER 54 and 57 along with HIS 58.

Zinc Binding

Zinc is an allosteric inhibitor to CzrA. Two Zn⁺² ions may bind to the dimer, at the location of the helix from each monomer. As zinc binds, the alpha 5 helices to inhibit the DNA binding residues. Furthermore, CzrA must be in its dimer form for zinc to bind. The is formed by two residues from each monomer, so Zn⁺² cannot bind to the monomer. The is formed by Asp84 and His86 from one monomer, and His97 and His100 from the other monomer. The zinc⁺² ion forms a tetrahedral complex with the four residues (Figure 1). This allows other metal ions to act as allosteric inhibitors to CzrA. Any metal that may form a tetrahedral complex will have some affinity for CzrA, assuming it is not too large to fit into the pocket. However, the metal binding pocket of CzrA has been optimized to bind Zn⁺² with the highest affinity. As CzrA is a transcriptional repressor, binding of Zn⁺² to the dimer will activate the czr operon. Zn⁺² is preferred as CzrB opens a Zn⁺² channel, allowing the excess zinc ions to export the cell.

Figure 1:Zn⁺² tetrahedral binding complex

References

↑ Hanson, R. M., Prilusky, J., Renjian, Z., Nakane, T. and Sussman, J. L. (2013), JSmol and the Next-Generation Web-Based Representation of 3D Molecular Structure as Applied to Proteopedia. Isr. J. Chem., 53:207-216. doi:http://dx.doi.org/10.1002/ijch.201300024
↑ Herraez A. Biomolecules in the computer: Jmol to the rescue. Biochem Mol Biol Educ. 2006 Jul;34(4):255-61. doi: 10.1002/bmb.2006.494034042644. PMID:21638687 doi:10.1002/bmb.2006.494034042644

Retrieved from "http://52.214.119.220/wiki/index.php/Sandbox_Reserved_1051"

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 == Structural Overview ==
-CzrA functions as a dimer. The <scene name='69/694218/Monomeric_unit/1'>monomeric units</scene> dimerize at the czr operon, repressing gene transcription. Each monomeric unit contains <scene name='69/694218/Helices/1'>five alpha helices</scene> seen in purple and <scene name='69/694218/B_sheets/1'>two beta sheets</scene> displayed in yellow. While the function of the beta sheets are not yet known, key helices regulate the binding of DNA and Zn<sup> +2 </sup>. The <scene name='69/694218/Alpha_4_helix/1'>alpha 4 helix</scene> is the location of DNA binding and the <scene name='69/694218/Alpha_5_helix/1'>alpha 5 helix</scene> contains the Zn<sup> +2 </sup> binding site. As Zn<sup> +2 </sup> binds, the alpha 4 helices are <scene name='69/694218/Alpha_4_helices_pushed/1'>pushed out of alignment</scene> repressing their DNA binding ability.
+CzrA functions as a dimer. The <scene name='69/694218/Monomeric_unit/1'>monomeric units</scene> dimerize at the czr operon, repressing gene transcription. Each monomeric unit contains <scene name='69/694218/Helices/1'>five alpha helices</scene> seen in purple and <scene name='69/694218/B_sheets/1'>two beta sheets</scene> displayed in yellow. While the function of the beta sheets are not yet known, key helices regulate the binding of DNA and Zn<sup> +2 </sup>. The <scene name='69/694218/Alpha_4_helix/1'>alpha 4 helix</scene> is the location of DNA binding and the <scene name='69/694218/Alpha_5_helix/1'>alpha 5 helix</scene> contains the Zn<sup> +2 </sup> binding site. As Zn<sup> +2 </sup> binds, the alpha 4 helices are <scene name='69/694218/Alpha_4_helices_pushed/1'>pushed out of alignment</scene>, repressing their DNA binding ability.
 == Binding of DNA ==

Sandbox Reserved 1051

From Proteopedia

Revision as of 12:50, 28 March 2017

CzrA

Contents

Biological Function

Structural Overview

Binding of DNA

Zinc Binding

References

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