Schematic Drawing of the Active Site of the Calcium Pump that Completes the ATP Cleavage Reaction (IMAGE)
Caption
The outline of this region of the protein (which is a long chain of 994 amino acid residues and approximately 15,000 atoms in total) is shown as white and yellow features and includes detailed representations of two catalytically important amino acid residues as red and white sticks (oxygen and carbon atoms). The red spheres represent bound water molecules, and the magenta sphere a magnesium ion that coordinates the phosphorylated amino acid side chain (an aspartic acid, lower) and the vanadate mimic of the phosphate "caught in the act" of cleavage (middle) by a water molecule positioned on top. The water is activated for the reaction by another catalytically active amino acid side chain (a glutamatic acid). This active site architecture is nearly identical in all ion pumps and responsible for approximately 1/3 of the ATP energy consumption in the human body.
Credit
Dr. Johannes Clausen
Usage Restrictions
Credit to Dr. Johannes Clausen
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