User:Ankit Vahia/sandbox1

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(Ligand-binding domain)
Current revision (15:46, 30 April 2010) (edit) (undo)
 
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[[Image:intactModelLargeText.jpg|frame|Bacterial chemotaxis receptor]]
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[Image:intactModelLargeText.jpg|frame|T7 RNA Polymerase in the Late Initiation Phase]
A [[CBI Molecule]] being studied in the [http://www.umass.edu/cbi/ University of Massachusetts Amherst Chemistry-Biology Interface Program] at UMass Amherst and on display at the [http://www.molecularplayground.org/ Molecular Playground].
A [[CBI Molecule]] being studied in the [http://www.umass.edu/cbi/ University of Massachusetts Amherst Chemistry-Biology Interface Program] at UMass Amherst and on display at the [http://www.molecularplayground.org/ Molecular Playground].
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Many bacteria can "smell" their surroundings and "choose" where to go. They detect molecules such as amino acids or sugars using receptors that bind these molecules and transmit a signal into the cell. This signal controls several proteins which ultimately control the direction of rotation of the motors that rotate the flagella. One direction causes the cell to continue swimming; the other direction causes the cell to tumble. When an attractant molecule binds, the receptor signals: "Things look good, keep swimming!" The opposite signal occurs when bacteria sense a repellant or less attractant molecules: "Time to tumble and try a new swimming direction."
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T7 RNA polymerase is a a single sub-unit DNA dependent RNA polymerase from the T7 bacteriophage. Like most RNA polymerase T7 RNA polymerase transcribes DNA through three phases
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-Initiation
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-Elongation
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-Termination
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The initiation phase continues until the enzyme synthesizes ~8 base RNA after which it loses promoter contacts and transitions into the stable elongation phase. The initiation phase in T7 RNA polymerase like all other single and multi subunit RNA polymerases is characterized by inherent instability leading to the release of small RNA (3-8 bases long). In addition to the crystal structure of the enzyme with a 3 base DNA-RNA hybrid (PDB ID:1QLN) this 7 base intermediate structure provides a insight into the structural changes within the enzyme has it synthesizes RNA during initiation and the mechanism which eventually leads to the release of the promoter contacts and the transition into elongation.
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In the image below, the template strand (blue) has been separated from the non-template strand (green) and forms a 7 base hybrid with the RNA (red).
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A bacterial chemotaxis receptor is an unusually long alpha-helical structure. The attractant molecule (the ligand) binds near the top of this picture and sends a signal across the membrane into the cell to control proteins that bind near the bottom. This is a model of the structure of the receptor based on experimental structures of pieces of related proteins.
 
{{Clear}}
{{Clear}}
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<applet load='1wat' size='[450,338]' frame='true' align='right'
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<applet load='3E2E' size='[450,338]' frame='true' align='right'
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caption='Aspartate receptor ligand binding domain (1wat)' scene='User:Lynmarie_K_Thompson/Sandbox_1/Loadedfrompdb/4'/>
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caption='Aspartate receptor ligand binding domain (1wat)' scene='User:Ankit_Vahia/sandbox1/T7-7mer_rna_scene_2/2'>TextToBeDisplayed</scene>
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=== Ligand-binding domain ===
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The spinning protein (<scene name='User:Ankit_Vahia/sandbox1/T7-7mer_rna_scene_1/1'>TextToBeDisplayed</scene>) ) is the ligand binding domain of the aspartate receptor with the aspartate ligand bound (LKT).
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Molecular Playground banner: A receptor protein used by bacteria to "smell" their environment.
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Current revision

[Image:intactModelLargeText.jpg|frame|T7 RNA Polymerase in the Late Initiation Phase]

A CBI Molecule being studied in the University of Massachusetts Amherst Chemistry-Biology Interface Program at UMass Amherst and on display at the Molecular Playground.

T7 RNA polymerase is a a single sub-unit DNA dependent RNA polymerase from the T7 bacteriophage. Like most RNA polymerase T7 RNA polymerase transcribes DNA through three phases -Initiation -Elongation -Termination

The initiation phase continues until the enzyme synthesizes ~8 base RNA after which it loses promoter contacts and transitions into the stable elongation phase. The initiation phase in T7 RNA polymerase like all other single and multi subunit RNA polymerases is characterized by inherent instability leading to the release of small RNA (3-8 bases long). In addition to the crystal structure of the enzyme with a 3 base DNA-RNA hybrid (PDB ID:1QLN) this 7 base intermediate structure provides a insight into the structural changes within the enzyme has it synthesizes RNA during initiation and the mechanism which eventually leads to the release of the promoter contacts and the transition into elongation.

In the image below, the template strand (blue) has been separated from the non-template strand (green) and forms a 7 base hybrid with the RNA (red).


Aspartate receptor ligand binding domain (1wat)

Drag the structure with the mouse to rotate

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Ankit Vahia

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