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== Introduction ==
== Introduction ==
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The tetanus toxin, or ''Clostridium tetani'', is produced by the bacteria Clostridium. Clostridium bacteria produces distinct neurotoxins that are extremely potent to humans. It releases two types of neurotoxins: ''Clostridium botulinum'' and ''Clostridium tetani''. It is part of the peptidase M27 family of proteins, which are metalloproteases. Metalloproteases bind with a divalent cation, usually zinc, which activates water molecules within the active site to hydrolyze peptide bonds.
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The tetanus toxin is produced by the bacteria ''Clostridium tetani''. Clostridium bacteria produces distinct neurotoxins that are extremely potent to humans. Both ''Clostridium botulinum'' and ''Clostridium tetani'' form the clostridial neurotoxin family. This family is classified as part of the peptidase M27 family of proteins, which are metalloproteases. Metalloproteases bind with a divalent cation, usually zinc, which activates water molecules within the active site to hydrolyze peptide bonds.
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''Clostridium tetani'' functions by inhibiting neurotransmitter release into the synaptic cleft of the spinal cord. It mimics a zinc peptidase
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The tetanus toxin effects the central nervous system by inhibiting the release of neurotransmitters, glycine and gamma-aminobutyric acid, into the synaptic cleft of the spinal cord. This causes spastic paralysis, or tetanus.
The toxin is produced after the bacterial cell's active, exponential growth phase.
The toxin is produced after the bacterial cell's active, exponential growth phase.
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== Structure ==
== Structure ==
<Structure load='1YVG' size='500' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' />
<Structure load='1YVG' size='500' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' />
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The ''Clostridium tetani'' precursor polypeptide is cleaved during cell autolysis into a heavy and light chains. These two chains remain linked by a disulfide bridge. These chains are non-toxic when separated.
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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.
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The heavy chain is involved in binding and the light chain is involved in biological activity.
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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.
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== Mechanism of Action ==
== Mechanism of Action ==
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Tetanus toxin binds to the neural cells through gangliosides and a second protein receptor. Once bound, they enter the cytosol via a vesicle membrane. Here, they attack and cleave the proteins that forms the synaptic vesicle fusion apparatus.
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== Medical Implications or Possible Applications ==
== Medical Implications or Possible Applications ==
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Tetanus toxin is still a main concern to public health taking several hundred lives each year.

Revision as of 17:24, 1 May 2012

Contents

TETANUS TOXIN

This Sandbox is Reserved from 13/03/2012, through 01/06/2012 for use in the course "Proteins and Molecular Mechanisms" taught by Robert B. Rose at the North Carolina State University, Raleigh, NC USA. This reservation includes Sandbox Reserved 451 through Sandbox Reserved 500.
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Introduction

The tetanus toxin is produced by the bacteria Clostridium tetani. Clostridium bacteria produces distinct neurotoxins that are extremely potent to humans. Both Clostridium botulinum and Clostridium tetani form the clostridial neurotoxin family. This family is classified as part of the peptidase M27 family of proteins, which are metalloproteases. Metalloproteases bind with a divalent cation, usually zinc, which activates water molecules within the active site to hydrolyze peptide bonds.

The tetanus toxin effects the central nervous system by inhibiting the release of neurotransmitters, glycine and gamma-aminobutyric acid, into the synaptic cleft of the spinal cord. This causes spastic paralysis, or tetanus.

The toxin is produced after the bacterial cell's active, exponential growth phase.


Structure

Insert caption here

Drag the structure with the mouse to rotate

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.

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.



Mechanism of Action

Tetanus toxin binds to the neural cells through gangliosides and a second protein receptor. Once bound, they enter the cytosol via a vesicle membrane. Here, they attack and cleave the proteins that forms the synaptic vesicle fusion apparatus.



Medical Implications or Possible Applications

Tetanus toxin is still a main concern to public health taking several hundred lives each year.

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