Ouabain: Difference between revisions

Below is the structure of oubain in two dimensions.  The molecule consists of a sugar bound to a modified cholesterol by a glycosidic linkage (hence ''glycoside'').  The hydroxyl groups surrounding much of the molecule, along with the esters at either end, contribute to its binding to the membrane bound sodium-potassium pump.  <scene name='Sandbox_60/Ouabain_3d/1'>Ouabain</scene> can also be seen in three dimensions.  With the molecular geometry and stereochemistry displayed in this way, one can see more clearly the distribution of polar carbon-oxygen and non-polar carbon-carbon bonds in the space surrounding the molecule.  This makes visualizing the binding of the inhibitor much easier.[[Image:Ouabain.png|thumb|left|upright=1.5]]  Ouabain is <scene name='Sandbox_60/Drug_in_complex/1'>bound</scene> to the protein along the inside of an alpha-helix bundle. <scene name='Sandbox_60/Drug_in_complex_np/1'>Non-polar</scene> components of residues help somewhat in coordinating ouabain through Van der Waals forces, but <scene name='Sandbox_60/Drug_in_complex_p/1'>polar</scene> residues, glutamine, aspartic acid, and threonine, along with the amide bond of an alanine, surround the hydroxyl and carbonyl groups of the ligand, forming hydrogen bonds of 2 to 4 angstroms in length. This not only holds the drug in place, but prevents conformational change necessary for the function of the protein.