Sandbox Reserved 1056: Difference between revisions

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OCA, Braden Sciarra, Garrett Oberst, Geoffrey C. Hoops, Douglas Schnell

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 ===Catalytic Loop===
 [[Image:Openvsclosed..png|400 px|left|thumb|Figure 4: Open (Blue) vs. Closed (Red) conformation of the active site loop of ICL.  Glyoxylate is shown in yellow and succinate in purple.  Hydrogen bonding is shown between LYS189 and the catalytic loop.]]
-The catalytic loop of the Isocitrate Lyase enzyme is composed of residues 185-196, and can exist in both the open and closed conformation (see Figure 4). In the open conformation, the catalytic loop is oriented such that the catalytic CYS191 residue is located far from the active site, allowing for solvent accessibility and substrate binding.<ref name="solvent">Connely, M. L. Solvent-accessible surfaces of proteins and nucleic acids "Science" 221:709-713 (1983). DOI: 10.1126/science.6879170</ref> Upon substrate binding, the catalytic loop, shown in blue, adopts a <scene name='69/694223/Catalytic_loop/2'>closed loop</scene> conformation, moving between ten and fifteen angstroms<ref name="ICL">PMID:10932251</ref>. This closed conformation will cause the binding site to become inaccessible to the solvent. The loop closure is triggered by the movement of the Mg ion that occurs upon binding of the succinate.  This movement of the Mg ion results in electrostatic interactions at LYS189, causing the loop to close.
+The catalytic loop of the Isocitrate Lyase enzyme is composed of residues 185-196, and can exist in both the open and closed conformation (see Figure 4). In the open conformation, the catalytic loop is oriented such that the catalytic CYS191 residue is located far from the active site, allowing for solvent accessibility and substrate binding.<ref name="solvent">Connely, M. L. Solvent-accessible surfaces of proteins and nucleic acids "Science" 221:709-713 (1983). DOI: 10.1126/science.6879170</ref> Upon substrate binding, the catalytic loop, shown in blue, adopts a <scene name='69/694223/Catalytic_loop/2'>closed loop</scene> conformation, moving between ten and fifteen angstroms.<ref name="ICL">PMID:10932251</ref> This closed conformation will cause the binding site to become inaccessible to the solvent. The loop closure is triggered by the movement of the Mg ion that occurs upon binding of the succinate.  This movement of the Mg ion results in electrostatic interactions at LYS189, causing the loop to close.
 ==Elucidation of ICL Structure Using Inhibitors==