Sandbox 172: Difference between revisions

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The size of hexokinase type I is approximately 100 kD. Hexokinase type I is constructed by a N-terminal regulatory domain and a C-terminal catalytic domain joined together by an alpha helix. The glucose binding site of hexokinase type I can be found within the two sub-units that make up the isoenzyme, these are known as lobes. Factors that contribute to the binding of glucose to this active site include amino acids within the actual site and hydrogen bonding that takes place on the glucose between the hydroxyl groups.
The size of hexokinase type I is approximately 100 kD. Hexokinase type I is constructed by a N-terminal regulatory domain and a C-terminal catalytic domain joined together by an alpha helix. The glucose binding site of hexokinase type I can be found within the two sub-units that make up the isoenzyme, these are known as lobes. Factors that contribute to the binding of glucose to this active site include amino acids within the actual site and hydrogen bonding that takes place on the glucose between the hydroxyl groups.
===Glucose Binding Sites===
===Glucose Binding Sites===
The residues of the glucose binding site of Hexokinase Type I are very highly conserved within the hexokinase sequence; glucose binds equally to both domains or "lobes" of the structure. As a result, hexokinase type I in its native conformation has an active site in its inactive regulatory domains.
The residues of the glucose binding site of Hexokinase Type I are very highly conserved within the hexokinase sequence; glucose binds equally to both domains or "lobes" of the structure. As a result, hexokinase type I in its native conformation has an active site in its inactive regulatory domains. Before glucose binds to hexokinase type I, it is said to be in an open conformation. ATP is already bound within one of the domains but it is situated a distance from the glucose binding site. As the glucose binds, the two domains close around the glucose substrate and this change results in a newly formed pattern of hydrogen bonding.
===Active Site===
===Active Site===
In the <scene name='Sandbox_172/Mynewscene/2'>active site</scene> of hexokinase type I, Lys 621 and Asp 657 show the hydrogen-bonding distance in which a reactive O6 hydroxyl is situated in between.
In the <scene name='Sandbox_172/Mynewscene/2'>active site</scene> of hexokinase type I, Lys 621 and Asp 657 show the hydrogen-bonding distance in which a reactive O6 hydroxyl is situated in between.