Sandbox Reserved 1061: Difference between revisions
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The <scene name='69/694228/Nrdh_structure/1'>MtNrdH structure</scene> determined by x-ray crystallography has 79 residues in a single polypeptide chain. The active site (shown in green) is dominated by a <scene name='69/694228/Nrdh_structure/3'>disulfide bond</scene> between Cys-11 and Cys-14, which serves as the site of reduction by thioredoxin reductase. <ref name="Swastik" /> | The <scene name='69/694228/Nrdh_structure/1'>MtNrdH structure</scene> determined by x-ray crystallography has 79 residues in a single polypeptide chain. The active site (shown in green) is dominated by a <scene name='69/694228/Nrdh_structure/3'>disulfide bond</scene> between Cys-11 and Cys-14, which serves as the site of reduction by thioredoxin reductase. <ref name="Swastik" /> | ||
Many thioredoxin-like proteins have a similar active site region, which includes the <scene name='69/694228/Nrdh_structure/4'>thioredoxin fold</scene>, a large turn in the protein structure right before the disulfide bond. The residues directly following the fold, <scene name='69/694228/Nrdh_structure/5'>CVQC</scene>, are the most highly conserved of all areas of the protein across multiple species. Exactly how this structure relates to function is somewhat debated, but it is hypothesized that the fold allows residues preceding the turn to interact with the CVQC motif after the turn. A threonine-7 reside directly across the thioredoxin fold from the disulfide bond has been suggested to adopt two different conformations which differentially affect the redox abilities of the protein. In the <scene name='69/694228/Nrdh_ligand_binding_site/17'>"A" conformation</scene>, the alcohol of the threonine side chain points towards the disulfide bond, engaging | Many thioredoxin-like proteins have a similar active site region, which includes the <scene name='69/694228/Nrdh_structure/4'>thioredoxin fold</scene>, a large turn in the protein structure right before the disulfide bond. The residues directly following the fold, <scene name='69/694228/Nrdh_structure/5'>CVQC</scene>, are the most highly conserved of all areas of the protein across multiple species. Exactly how this structure relates to function is somewhat debated, but it is hypothesized that the fold allows residues preceding the turn to interact with the CVQC motif after the turn. A threonine-7 reside directly across the thioredoxin fold from the disulfide bond has been suggested to adopt two different conformations which differentially affect the redox abilities of the protein. In the <scene name='69/694228/Nrdh_ligand_binding_site/17'>"A" conformation</scene>, the alcohol oxygen of the threonine side chain (seen as a red ball) points towards the disulfide bond, engaging a electrostatic interaction (represented by a short dashed line) between the two that prevents thioredoxin reductase from binding. Alternatively, in the <scene name='69/694228/Nrdh_ligand_binding_site/16'>"B" Conformation</scene>, the alcohol points in the opposite direction, allowing sufficient space and enough electrostatic freedom for the ligand to bind and reduction to occur.<ref name="Swastik" /> | ||
The active site of the protein is stabilized through a <scene name='69/696879/Water_coordination/1'>hydrogen bond network</scene> involving the two highly conserved residues, CVQC (green) and [http://www.proteopedia.org/wiki/index.php/Image:Weblogowsgfrp.png WSGFRP] (yellow). The crystal structure shows that interactions with one water molecule is necessary for the proper coordination between the conserved motifs to occur. These hydrogen bonds orient the important residues in the most optimal position to promote oxidation and reduction.<ref name="Swastik" /> | The active site of the protein is stabilized through a <scene name='69/696879/Water_coordination/1'>hydrogen bond network</scene> involving the two highly conserved residues, CVQC (green) and [http://www.proteopedia.org/wiki/index.php/Image:Weblogowsgfrp.png WSGFRP] (yellow). The crystal structure shows that interactions with one water molecule is necessary for the proper coordination between the conserved motifs to occur. These hydrogen bonds orient the important residues in the most optimal position to promote oxidation and reduction.<ref name="Swastik" /> | ||
