Sandbox Reserved 1061: Difference between revisions
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The structure of ''M. tuberculosis'' as determined by x-ray crystallography has 79 residues in a single polypeptide chain. <scene name='69/694228/Nrdh_structure/1'>NrdH Chrystal Structure</scene>. The active site (shown in green) is dominated by a disulphide bond between Cys-11 and Cys-14, which serves as the site of reduction by Theirodoxin reductase. | The structure of ''M. tuberculosis'' as determined by x-ray crystallography has 79 residues in a single polypeptide chain. <scene name='69/694228/Nrdh_structure/1'>NrdH Chrystal Structure</scene>. The active site (shown in green) is dominated by a disulphide bond between Cys-11 and Cys-14, which serves as the site of reduction by Theirodoxin reductase. | ||
Many theirodoxin-like proteins have a similar active site region, denoted as the theirodoxin fold, which occurs directly before the disulfide bond. The residues in this region, denoted by letters CVQC, are the most highly conserved of all areas of the protein across multiple species. Exactly how this structure relates to function is somewhat debated. A Threonine-7 reside directly across the theirodoxin fold from the disulphide 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/8'>"A" Conformation</scene>, the alcohol of the threonine side chain points towards the disulfide bond, engaging an ionic interaction between the two that prevents the Therodoxin Reductase from binding. | Many theirodoxin-like proteins have a similar active site region, denoted as the theirodoxin fold, which occurs directly before the disulfide bond. The residues in this region, denoted by letters CVQC, are the most highly conserved of all areas of the protein across multiple species. Exactly how this structure relates to function is somewhat debated. A Threonine-7 reside directly across the theirodoxin fold from the disulphide 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/8'>"A" Conformation</scene>, the alcohol of the threonine side chain points towards the disulfide bond, engaging an ionic interaction between the two that prevents the Therodoxin Reductase from binding. Alternatively, in the <scene name='69/694228/Nrdh_ligand_binding_site/12'>"B" Conformation</scene>, the alcohol points in the opposite direction, allowing sufficient space for the ligand to bind and reduction to occur. | ||
The active site of the protein is stabilized through a network of hydrogen bonds involving the two highly conserved residues, CVQC and WSGFRP. 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. | The active site of the protein is stabilized through a network of hydrogen bonds involving the two highly conserved residues, CVQC and WSGFRP. 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. | ||
