Sandbox Reserved 982
From Proteopedia
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{{Telford_CHEM321}}<!-- PLEASE ADD YOUR CONTENT BELOW HERE --> | {{Telford_CHEM321}}<!-- PLEASE ADD YOUR CONTENT BELOW HERE --> | ||
| - | == | + | ==Shiga Toxin== |
<StructureSection load='1R4Q' size='340' side='right' caption='Crystal Structure for Shiga Toxin (1R4Q)' scene=''> | <StructureSection load='1R4Q' size='340' side='right' caption='Crystal Structure for Shiga Toxin (1R4Q)' scene=''> | ||
| - | == | + | == Structural Highlights == |
<scene name='68/687332/Shiga_toxin/5'>Crystal Structure of Shiga Toxin</scene> | <scene name='68/687332/Shiga_toxin/5'>Crystal Structure of Shiga Toxin</scene> | ||
Stx is composed of two main subunits labeled A and B. The A subunit bonds noncovalently to the B subunit. The A subunit is 293 amino acids long with its active site being glutamic acid 167. Studies have shown that the first 239 residues are essential for the enzymatic activity of the A subunit. The B subunit is a pentamer that resembles a star and can be divided into five identical subunits. Each of the subunits is 69 amino acids in length. The purpose of the B subunit is to bind to globotriaosylceramide (GB3) which is a glycosphingolipid that resides on the surface of some Eukaryotic cells. Each monomer of the B subunit has three binding sites for GB3 making the protein very potent (Melton-Celsa 2013). | Stx is composed of two main subunits labeled A and B. The A subunit bonds noncovalently to the B subunit. The A subunit is 293 amino acids long with its active site being glutamic acid 167. Studies have shown that the first 239 residues are essential for the enzymatic activity of the A subunit. The B subunit is a pentamer that resembles a star and can be divided into five identical subunits. Each of the subunits is 69 amino acids in length. The purpose of the B subunit is to bind to globotriaosylceramide (GB3) which is a glycosphingolipid that resides on the surface of some Eukaryotic cells. Each monomer of the B subunit has three binding sites for GB3 making the protein very potent (Melton-Celsa 2013). | ||
== Function == | == Function == | ||
The pathway of stx entering a cell begins with the B subunit’s binding to GB3. Once this occurs, the A subunit disconnects from the B subunit and enters the cell through endocytosis. Using retrograde transport the A subunit passes through the Golgi apparatus and the rough endoplasmic reticulum. In the rough endoplasmic reticulum, the A subunit is cleaved into two parts called A1 and A2. A2 is degraded, but A1 freely enters the cytosol (Sandvig 2000). Once in the cytosol, A1 acts as an N-glycosidase, which is an enzyme that hydrolyzes bonds that link sugars. With this enzymatic activity, A1 removes adenines from the 28S RNA of the 60S ribosomal subunit (Melton-Celsa 2013). This inhibits protein synthesis and ultimately leads to cell death. | The pathway of stx entering a cell begins with the B subunit’s binding to GB3. Once this occurs, the A subunit disconnects from the B subunit and enters the cell through endocytosis. Using retrograde transport the A subunit passes through the Golgi apparatus and the rough endoplasmic reticulum. In the rough endoplasmic reticulum, the A subunit is cleaved into two parts called A1 and A2. A2 is degraded, but A1 freely enters the cytosol (Sandvig 2000). Once in the cytosol, A1 acts as an N-glycosidase, which is an enzyme that hydrolyzes bonds that link sugars. With this enzymatic activity, A1 removes adenines from the 28S RNA of the 60S ribosomal subunit (Melton-Celsa 2013). This inhibits protein synthesis and ultimately leads to cell death. | ||
| - | == | + | == Function == |
| - | == | + | == Disease and It's Pathogenesis == |
| - | == Structural highlights == | ||
This is a sample scene created with SAT to <scene name='68/687332/Scene_1/1'>TextToBeDisplayed</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes. | This is a sample scene created with SAT to <scene name='68/687332/Scene_1/1'>TextToBeDisplayed</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes. | ||
Revision as of 03:53, 1 May 2015
| This Sandbox is Reserved from 15-Jan-2015, through 30-May-2015 for use in the course "Biochemistry" taught by Jason Telford at the Maryville University. This reservation includes Sandbox Reserved 977 through Sandbox Reserved 986. |
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Shiga Toxin
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