Sandbox Reserved 466: Difference between revisions

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The precursor polypeptide of the tetanus toxin is cleaved during post-translational modification into a heavy and light chains. These two chains remain linked by a disulfide bridge. The heavy chain is the C-terminal end of the protein and the light chain is the N-terminal end of the protein. If the two chains are separated, the toxin becomes non-toxic [PDB].

Tetanus toxin has three functional domains: binding, translocation, and catalytic. The heavy chain is responsible for binding the toxin to the specific neural receptors and translocating the catalytic light chain domain into the neural cytosol. The light chain is the zinc-binding domain containing a zinc-binding motif. This metalloprotease activity causes toxicity [Krishnamurthy et al., 2005]. The light chain forms a dimer with about 10% of the protein surface existing between the two monomers. Each monomer binds one zinc ion. The active sites of the light chain tetanus toxin interact with the solvent region and are embedded inside a cavity centered around a zinc cation and the conserved zinc-dependent motif. Zinc directly coordinates with His232, His236, and Glu270 within the <scene name='Sandbox_Reserved_466/Zinc_binding_active_site/1'>Zinc binding active site</scene>. Water is another ligand that forms a hydrogen bond with Glu233. The formation of the nucleophilic water molecule and the three other amino acid residues in the active site form a tetrahedral configuration around the catalytic zinc ion. This interaction between the residues, water, and zinc are essential for the formation of nucleophilic water, which hydrolyzes the peptide bonds of the substrate. There is also a secondary layer important to the functionality of the active site. These residues are in the surrounding structure, approximately 10 Angstroms from the zinc ion, and they include Glu233, His239, Phe274, Arg371, and Tyr374. These residues reinforce the stability and conformation of the active site. The active site is illustrated ~~in the figure below~~.

Tetanus toxin has three functional domains: binding, translocation, and catalytic. The heavy chain is responsible for binding the toxin to the specific neural receptors and translocating the catalytic light chain domain into the neural cytosol. The light chain is the zinc-binding domain containing a zinc-binding motif. This metalloprotease activity causes toxicity [Krishnamurthy et al., 2005]. The light chain forms a dimer with about 10% of the protein surface existing between the two monomers. Each monomer binds one zinc ion. The active sites of the light chain tetanus toxin interact with the solvent region and are embedded inside a cavity centered around a zinc cation and the conserved zinc-dependent motif. Zinc directly coordinates with His232, His236, and Glu270 within the <scene name='Sandbox_Reserved_466/Zinc_binding_active_site/1'>Zinc binding active site</scene>. Water is another ligand that forms a hydrogen bond with Glu233. The formation of the nucleophilic water molecule and the three other amino acid residues in the [http://www.sciencedirect.com/science/article/pii/S0041010105000929#gr1 active site] form a tetrahedral configuration around the catalytic zinc ion. This interaction between the residues, water, and zinc are essential for the formation of nucleophilic water, which hydrolyzes the peptide bonds of the substrate. There is also a secondary layer important to the functionality of the active site. These residues are in the surrounding structure, approximately 10 Angstroms from the zinc ion, and they include Glu233, His239, Phe274, Arg371, and Tyr374. These residues reinforce the stability and conformation of the active site. The active site is illustrated .

Sandbox Reserved 466: Difference between revisions

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Revision as of 18:52, 1 May 2012 view source Justyne Hammond (talk \| contribs) 51 edits No edit summary ← Older edit		Revision as of 01:16, 2 May 2012 view source Justyne Hammond (talk \| contribs) 51 edits No edit summary Newer edit →
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	The precursor polypeptide of the tetanus toxin is cleaved during post-translational modification into a heavy and light chains. These two chains remain linked by a disulfide bridge. The heavy chain is the C-terminal end of the protein and the light chain is the N-terminal end of the protein. If the two chains are separated, the toxin becomes non-toxic [PDB].		The precursor polypeptide of the tetanus toxin is cleaved during post-translational modification into a heavy and light chains. These two chains remain linked by a disulfide bridge. The heavy chain is the C-terminal end of the protein and the light chain is the N-terminal end of the protein. If the two chains are separated, the toxin becomes non-toxic [PDB].

	Tetanus toxin has three functional domains: binding, translocation, and catalytic. The heavy chain is responsible for binding the toxin to the specific neural receptors and translocating the catalytic light chain domain into the neural cytosol. The light chain is the zinc-binding domain containing a zinc-binding motif. This metalloprotease activity causes toxicity [Krishnamurthy et al., 2005]. The light chain forms a dimer with about 10% of the protein surface existing between the two monomers. Each monomer binds one zinc ion. The active sites of the light chain tetanus toxin interact with the solvent region and are embedded inside a cavity centered around a zinc cation and the conserved zinc-dependent motif. Zinc directly coordinates with His232, His236, and Glu270 within the <scene name='Sandbox_Reserved_466/Zinc_binding_active_site/1'>Zinc binding active site</scene>. Water is another ligand that forms a hydrogen bond with Glu233. The formation of the nucleophilic water molecule and the three other amino acid residues in the active site form a tetrahedral configuration around the catalytic zinc ion. This interaction between the residues, water, and zinc are essential for the formation of nucleophilic water, which hydrolyzes the peptide bonds of the substrate. There is also a secondary layer important to the functionality of the active site. These residues are in the surrounding structure, approximately 10 Angstroms from the zinc ion, and they include Glu233, His239, Phe274, Arg371, and Tyr374. These residues reinforce the stability and conformation of the active site. The active site is illustrated ~~in the figure below~~.		Tetanus toxin has three functional domains: binding, translocation, and catalytic. The heavy chain is responsible for binding the toxin to the specific neural receptors and translocating the catalytic light chain domain into the neural cytosol. The light chain is the zinc-binding domain containing a zinc-binding motif. This metalloprotease activity causes toxicity [Krishnamurthy et al., 2005]. The light chain forms a dimer with about 10% of the protein surface existing between the two monomers. Each monomer binds one zinc ion. The active sites of the light chain tetanus toxin interact with the solvent region and are embedded inside a cavity centered around a zinc cation and the conserved zinc-dependent motif. Zinc directly coordinates with His232, His236, and Glu270 within the <scene name='Sandbox_Reserved_466/Zinc_binding_active_site/1'>Zinc binding active site</scene>. Water is another ligand that forms a hydrogen bond with Glu233. The formation of the nucleophilic water molecule and the three other amino acid residues in the [http://www.sciencedirect.com/science/article/pii/S0041010105000929#gr1 active site] form a tetrahedral configuration around the catalytic zinc ion. This interaction between the residues, water, and zinc are essential for the formation of nucleophilic water, which hydrolyzes the peptide bonds of the substrate. There is also a secondary layer important to the functionality of the active site. These residues are in the surrounding structure, approximately 10 Angstroms from the zinc ion, and they include Glu233, His239, Phe274, Arg371, and Tyr374. These residues reinforce the stability and conformation of the active site. The active site is illustrated .