Sandbox Reserved 492: Difference between revisions

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== Cholix Toxin from ''Vibrio Cholerae ''==

The [http://en.wikipedia.org/wiki/Crystal_structure crystal structure] of the purified form of ''' Cholix Toxin''' or '''CT''' was determined in 1995. [3] It is an oligomeric bacterial protein found to be made up of six individual <scene name='Sandbox_Reserved_496/Secondary_structure/1'>~~subunits,~~ </scene> one single α-subunit and 5 individual β- subunits.The α-subunit makes up what is known as the enzymatic portion of the protein while the 5 copies of the β-subunit are responsible for the binding to the ligand receptor. The toxin binds highly specifically and tightly to a [http://en.wikipedia.org/wiki/GM1_gangliosidoses GM1 gangliosides] on the surface of the host's cells. In this X-Ray Diffraction image we can see the <scene name='Sandbox_Reserved_496/Binding_site/1'>catalytic</scene> site, which in this case has been complexed with an allosteric inhibitor (red and yellow space filling atoms). Recent studies have indicated several amino acid <scene name='Sandbox_Reserved_496/Critical_amino_acids/2'> residues </scene> located proximally to the active site which are critical for enzymatic activity. Specifically, site directed mutagenesis indicated that when altered, the mutation results in a termination of the proteins toxicity, rendering it essentially harmless.

The [http://en.wikipedia.org/wiki/Crystal_structure crystal structure] of the purified form of ''' Cholix Toxin''' or '''CT''' was determined in 1995. [3] It is an oligomeric bacterial protein found to be made up of six individual subunits. V. cholerae toxin, along with other similar bacterial enterotoxins seem to share an evolutionary conserved <scene name='Sandbox_Reserved_496/Secondary_structure/1'> secondary structure </scene> composition comprising of about 13 alpha-helices and 10-12 Beta-sheets. The protein is then further divided into one single A-subunit and 5 individual B- subunits.The A-subunit makes up what is known as the enzymatic portion of the protein while the 5 copies of the B-subunit are responsible for the binding to the ligand receptor. The toxin binds highly specifically and tightly to a [http://en.wikipedia.org/wiki/GM1_gangliosidoses GM1 gangliosides] on the surface of the host's cells. In this X-Ray Diffraction image we can see the <scene name='Sandbox_Reserved_496/Binding_site/1'>catalytic</scene> site, which in this case has been complexed with an allosteric inhibitor (red and yellow space filling atoms). Recent studies have indicated several amino acid <scene name='Sandbox_Reserved_496/Critical_amino_acids/2'> residues </scene> located proximally to the active site which are critical for enzymatic activity. Specifically, site directed mutagenesis indicated that when altered, the mutation results in a termination of the proteins toxicity, rendering it essentially harmless.

Sandbox Reserved 492: Difference between revisions

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 <Structure load='3ki4' size='300' color='white' frame='true' align='right' caption='X-Ray Diffraction image at 2.1Å of Cholix Toxin from Vibrio Cholerae' />
 == Cholix Toxin from ''Vibrio Cholerae ''==
-The [http://en.wikipedia.org/wiki/Crystal_structure crystal structure] of the purified form of ''' Cholix Toxin''' or '''CT''' was determined in 1995. [3] It is an oligomeric bacterial protein found to be made up of six individual <scene name='Sandbox_Reserved_496/Secondary_structure/1'>subunits, </scene> one single α-subunit and 5 individual β- subunits.The α-subunit makes up what is known as the enzymatic portion of the protein while the 5 copies of the β-subunit are responsible for the binding to the ligand receptor. The toxin binds highly specifically and tightly to a [http://en.wikipedia.org/wiki/GM1_gangliosidoses GM1 gangliosides] on the surface of the host's cells. In this X-Ray Diffraction image we can see the <scene name='Sandbox_Reserved_496/Binding_site/1'>catalytic</scene> site, which in this case has been complexed with an allosteric inhibitor (red and yellow space filling atoms). Recent studies have indicated several amino acid <scene name='Sandbox_Reserved_496/Critical_amino_acids/2'> residues </scene> located proximally to the active site which are critical for enzymatic activity. Specifically, site directed mutagenesis indicated that when altered, the mutation results in a termination of the proteins toxicity, rendering it essentially harmless.
+The [http://en.wikipedia.org/wiki/Crystal_structure crystal structure] of the purified form of ''' Cholix Toxin''' or '''CT''' was determined in 1995. [3] It is an oligomeric bacterial protein found to be made up of six individual subunits. V. cholerae toxin, along with other similar bacterial enterotoxins seem to share an evolutionary conserved <scene name='Sandbox_Reserved_496/Secondary_structure/1'> secondary structure </scene> composition comprising of about 13 alpha-helices and 10-12 Beta-sheets. The protein is then further divided into one single A-subunit and 5 individual B- subunits.The A-subunit makes up what is known as the enzymatic portion of the protein while the 5 copies of the B-subunit are responsible for the binding to the ligand receptor. The toxin binds highly specifically and tightly to a [http://en.wikipedia.org/wiki/GM1_gangliosidoses GM1 gangliosides] on the surface of the host's cells. In this X-Ray Diffraction image we can see the <scene name='Sandbox_Reserved_496/Binding_site/1'>catalytic</scene> site, which in this case has been complexed with an allosteric inhibitor (red and yellow space filling atoms). Recent studies have indicated several amino acid <scene name='Sandbox_Reserved_496/Critical_amino_acids/2'> residues </scene> located proximally to the active site which are critical for enzymatic activity. Specifically, site directed mutagenesis indicated that when altered, the mutation results in a termination of the proteins toxicity, rendering it essentially harmless.