1otg
From Proteopedia
(New page: 200px<br /><applet load="1otg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1otg, resolution 2.1Å" /> '''5-CARBOXYMETHYL-2-HYD...) |
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| - | [[Image:1otg.jpg|left|200px]]<br /><applet load="1otg" size=" | + | [[Image:1otg.jpg|left|200px]]<br /><applet load="1otg" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1otg, resolution 2.1Å" /> | caption="1otg, resolution 2.1Å" /> | ||
'''5-CARBOXYMETHYL-2-HYDROXYMUCONATE ISOMERASE'''<br /> | '''5-CARBOXYMETHYL-2-HYDROXYMUCONATE ISOMERASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | 5-Carboxymethyl-2-hydroxymuconate isomerase (CHMI) and 4-oxalocrotonate | + | 5-Carboxymethyl-2-hydroxymuconate isomerase (CHMI) and 4-oxalocrotonate tautomerase (4-OT) are enzymes that catalyze the isomerization of unsaturated ketones. They share a common enzyme mechanism, although they show a preference for different substrates. There is no apparent sequence homology between the enzymes. To investigate the molecular mechanism and the basis for their substrate specificity, we have determined the crystal structures of the two enzymes at high resolution. 4-OT is hexameric, with the subunits arranged with 32 symmetry. CHMI is trimeric and has extensive contacts between subunits, which include secondary structural elements. The central core of the CHMI monomer has a fold similar to a 4-OT dimer, but the secondary structural elements that form the subunit contacts around the 3-fold axis are different in the two enzymes. The region of greatest similarity between the two enzymes is a large pocket that is proposed to be the active site. The enzymes appear to operate via a "one-base" mechanism, and the possible role of residues in this pocket is discussed in view of this idea. Finally, the molecular basis for substrate specificity in the two enzymes is discussed. |
==About this Structure== | ==About this Structure== | ||
| - | 1OTG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1OTG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OTG OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Dauter, Z.]] | [[Category: Dauter, Z.]] | ||
| - | [[Category: Davies, G | + | [[Category: Davies, G J.]] |
| - | [[Category: Dodson, E | + | [[Category: Dodson, E J.]] |
| - | [[Category: Roper, D | + | [[Category: Roper, D I.]] |
| - | [[Category: Subramanya, H | + | [[Category: Subramanya, H S.]] |
| - | [[Category: Wigley, D | + | [[Category: Wigley, D B.]] |
| - | [[Category: Wilson, K | + | [[Category: Wilson, K S.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: hydroxymuconate]] | [[Category: hydroxymuconate]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:21:21 2008'' |
Revision as of 12:21, 21 February 2008
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5-CARBOXYMETHYL-2-HYDROXYMUCONATE ISOMERASE
Overview
5-Carboxymethyl-2-hydroxymuconate isomerase (CHMI) and 4-oxalocrotonate tautomerase (4-OT) are enzymes that catalyze the isomerization of unsaturated ketones. They share a common enzyme mechanism, although they show a preference for different substrates. There is no apparent sequence homology between the enzymes. To investigate the molecular mechanism and the basis for their substrate specificity, we have determined the crystal structures of the two enzymes at high resolution. 4-OT is hexameric, with the subunits arranged with 32 symmetry. CHMI is trimeric and has extensive contacts between subunits, which include secondary structural elements. The central core of the CHMI monomer has a fold similar to a 4-OT dimer, but the secondary structural elements that form the subunit contacts around the 3-fold axis are different in the two enzymes. The region of greatest similarity between the two enzymes is a large pocket that is proposed to be the active site. The enzymes appear to operate via a "one-base" mechanism, and the possible role of residues in this pocket is discussed in view of this idea. Finally, the molecular basis for substrate specificity in the two enzymes is discussed.
About this Structure
1OTG is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
Reference
Enzymatic ketonization of 2-hydroxymuconate: specificity and mechanism investigated by the crystal structures of two isomerases., Subramanya HS, Roper DI, Dauter Z, Dodson EJ, Davies GJ, Wilson KS, Wigley DB, Biochemistry. 1996 Jan 23;35(3):792-802. PMID:8547259
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