2cw6: Difference between revisions
New page: left|200px<br /> <applet load="2cw6" size="450" color="white" frame="true" align="right" spinBox="true" caption="2cw6, resolution 2.10Å" /> '''Crystal Structure o... |
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'''Crystal Structure of Human HMG-CoA Lyase: Insights into Catalysis and the Molecular Basis for Hydroxymethylglutaric Aciduria'''<br /> | '''Crystal Structure of Human HMG-CoA Lyase: Insights into Catalysis and the Molecular Basis for Hydroxymethylglutaric Aciduria'''<br /> | ||
==Overview== | ==Overview== | ||
3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase is a key enzyme in the | 3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase is a key enzyme in the ketogenic pathway that supplies metabolic fuel to extrahepatic tissues. Enzyme deficiency may be due to a variety of human mutations and can be fatal. Diminished activity has been explained based on analyses of recombinant human mutant proteins or, more recently, in the context of structural models for the enzyme. We report the experimental determination of a crystal structure at 2.1 A resolution of the recombinant human mitochondrial HMG-CoA lyase containing a bound activator cation and the dicarboxylic acid 3-hydroxyglutarate. The enzyme adopts a (betaalpha)(8) barrel fold, and the N-terminal barrel end is occluded. The structure of a physiologically relevant dimer suggests that substrate access to the active site involves binding across the cavity located at the C-terminal end of the barrel. An alternative hypothesis that involves substrate insertion through a pore proposed to extend through the barrel is not compatible with the observed structure. The activator cation ligands included Asn(275), Asp(42),His(233), and His(235); the latter three residues had been implicated previously as contributing to metal binding or enzyme activity. Arg(41), previously shown to have a major effect on catalytic efficiency, is also located at the active site. In the observed structure, this residue interacts with a carboxyl group of 3-hydroxyglutarate, the hydrolysis product of the competitive inhibitor 3-hydroxyglutaryl-CoA required for crystallization of human enzyme. The structure provides a rationale for the decrease in enzyme activity due to clinical mutations, including H233R, R41Q, D42H, and D204N, that compromise active site function or enzyme stability. | ||
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
2CW6 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with MG and 3HG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Hydroxymethylglutaryl-CoA_lyase Hydroxymethylglutaryl-CoA lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.3.4 4.1.3.4] Full crystallographic information is available from [http:// | 2CW6 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=3HG:'>3HG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Hydroxymethylglutaryl-CoA_lyase Hydroxymethylglutaryl-CoA lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.3.4 4.1.3.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2CW6 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Fu, Z.]] | [[Category: Fu, Z.]] | ||
[[Category: Hunt, J | [[Category: Hunt, J F.]] | ||
[[Category: Kim, J | [[Category: Kim, J J.P.]] | ||
[[Category: Miziorko, H | [[Category: Miziorko, H M.]] | ||
[[Category: Runquist, J | [[Category: Runquist, J A.]] | ||
[[Category: 3HG]] | [[Category: 3HG]] | ||
[[Category: MG]] | [[Category: MG]] | ||
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[[Category: ketogenic enzyme]] | [[Category: ketogenic enzyme]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:53:00 2008'' | ||
Revision as of 17:53, 21 February 2008
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Crystal Structure of Human HMG-CoA Lyase: Insights into Catalysis and the Molecular Basis for Hydroxymethylglutaric Aciduria
OverviewOverview
3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase is a key enzyme in the ketogenic pathway that supplies metabolic fuel to extrahepatic tissues. Enzyme deficiency may be due to a variety of human mutations and can be fatal. Diminished activity has been explained based on analyses of recombinant human mutant proteins or, more recently, in the context of structural models for the enzyme. We report the experimental determination of a crystal structure at 2.1 A resolution of the recombinant human mitochondrial HMG-CoA lyase containing a bound activator cation and the dicarboxylic acid 3-hydroxyglutarate. The enzyme adopts a (betaalpha)(8) barrel fold, and the N-terminal barrel end is occluded. The structure of a physiologically relevant dimer suggests that substrate access to the active site involves binding across the cavity located at the C-terminal end of the barrel. An alternative hypothesis that involves substrate insertion through a pore proposed to extend through the barrel is not compatible with the observed structure. The activator cation ligands included Asn(275), Asp(42),His(233), and His(235); the latter three residues had been implicated previously as contributing to metal binding or enzyme activity. Arg(41), previously shown to have a major effect on catalytic efficiency, is also located at the active site. In the observed structure, this residue interacts with a carboxyl group of 3-hydroxyglutarate, the hydrolysis product of the competitive inhibitor 3-hydroxyglutaryl-CoA required for crystallization of human enzyme. The structure provides a rationale for the decrease in enzyme activity due to clinical mutations, including H233R, R41Q, D42H, and D204N, that compromise active site function or enzyme stability.
DiseaseDisease
Known disease associated with this structure: HMG-CoA lyase deficiency OMIM:[246450]
About this StructureAbout this Structure
2CW6 is a Single protein structure of sequence from Homo sapiens with and as ligands. Active as Hydroxymethylglutaryl-CoA lyase, with EC number 4.1.3.4 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of human 3-hydroxy-3-methylglutaryl-CoA Lyase: insights into catalysis and the molecular basis for hydroxymethylglutaric aciduria., Fu Z, Runquist JA, Forouhar F, Hussain M, Hunt JF, Miziorko HM, Kim JJ, J Biol Chem. 2006 Mar 17;281(11):7526-32. Epub 2005 Dec 5. PMID:16330550
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