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Hexokinase

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== Conformational change associated with substrate binding ==
== Conformational change associated with substrate binding ==
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When hexokinase binds to glucose (one of its two substrates), it exhibits induced fit. This means that in the open form of the enzyme, the binding site is not fully formed. Upon binding glucose, hexokinase switches into a closed form, excluding aqueous solvent from the substrate. This is illustrated here <scene name='45/452482/Induced_fit/1'>comparing the structures of free and glucose-bound hexokinase</scene>.
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When hexokinase binds to glucose (one of its two substrates), it exhibits induced fit. This means that in the open form of the enzyme, the binding site is not fully formed. Upon binding glucose, hexokinase switches into a closed form, excluding aqueous solvent from the substrate. This is illustrated here <scene name='45/452482/Induced_fit/2'>comparing the structures of free and glucose-bound hexokinase</scene>.
<jmol>
<jmol>
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<script>anim off; delay 0.5; model 1</script>
<script>anim off; delay 0.5; model 1</script>
<text>Open</text>
<text>Open</text>
 +
<checked>true</checked>
</item>
</item>
<item>
<item>
<script>anim off; delay 0.5; model 2</script>
<script>anim off; delay 0.5; model 2</script>
<text>Close</text>
<text>Close</text>
 +
<checked>false</checked>
</item>
</item>
<item>
<item>
<script>anim mode palindrome; anim on</script>
<script>anim mode palindrome; anim on</script>
<text>Animate</text>
<text>Animate</text>
-
<checked>true</checked>
+
<checked>false</checked>
</item>
</item>
</jmolRadioGroup>
</jmolRadioGroup>
Line 43: Line 45:
It is a bit easier to see the extent and nature of the changes in this <jmol>
It is a bit easier to see the extent and nature of the changes in this <jmol>
<jmolLink>
<jmolLink>
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<script> script "/scripts/45/452482/Induced_fit/1.spt"; script "/wiki/images/a/a2/Storymorph.spt";
+
<script> script "/scripts/45/452482/Induced_fit/2.spt"; script "/wiki/images/a/a2/Storymorph.spt"; model 2; color background black;
structures = [{1.1},{1.2}];
structures = [{1.1},{1.2}];
domain2 = {82-210};
domain2 = {82-210};

Revision as of 18:22, 30 April 2021

Hexokinase I complex with ATP analog, glucose, glucose-phosphate and Mg+2 ion (PDB code 1qha)

Drag the structure with the mouse to rotate

Additional Resources

For additional information, see: Carbohydrate Metabolism

References

1.↑ Pollard-Knight D, Cornish-Bowden A. Mechanism of liver glucokinase. Mol Cell Biochem. 1982 Apr 30;44(2):71-80. PMID:7048063

2.↑ 2.0 2.1 Kamata K, Mitsuya M, Nishimura T, Eiki J, Nagata Y. Structural basis for allosteric regulation of the monomeric allosteric enzyme human glucokinase. Structure. 2004 Mar;12(3):429-38. PMID:15016359 doi:10.1016/j.str.2004.02.005

3.↑ Postic C, Shiota M, Magnuson MA. Cell-specific roles of glucokinase in glucose homeostasis. Recent Prog Horm Res. 2001;56:195-217. PMID:11237213

4.↑ Zeng C, Aleshin A, Hardie J, Harrison R, Fromm H. ATP-Binding site of Human Brain Hexokinase as Studied by Molecular Modeling and Site-Directed Mutagenesis. Biochem. 1996 Aug 6;35:13157-13164.

5.↑ hammes G, and Kochavi D. Studies of the Enzyme Hexokinase: Kinetic Inhibition by Products. Massachusetts Institute of Technology. 1961 Oct 5.

6.↑ Ralph E, Thomson J, Almaden J, Sun S. Glucose Modulation fo Glucokinase Activation by Small Molecules. Biochem. 2008 Feb 15;47:5028-5036.

7.↑ Pal P, and Miller B. Activating Mutations in the Human Glucokinase Gene Revealed by Genetic Selection. Biochem. 2008 Dec 3;48:814-816.

8.↑ Aleshin A, Malfois M, Liu X, Kim C, Fromm H, Honzatko R, Koch M, Svergun D. Nonaggregating Mutant of Recombinant Human Hexokinase I Exhibits Wild-Type Kinetics and Rod-like Conformations in Solution. Biochem. 1999 Apr 29;38:8359-8366.


Seth Bawel and Kyle_Schroering created this page in Che 361 at Wabash College.

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