2hdh
From Proteopedia
(New page: 200px<br /> <applet load="2hdh" size="450" color="white" frame="true" align="right" spinBox="true" caption="2hdh, resolution 2.20Å" /> '''BIOCHEMICAL CHARACT...) |
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caption="2hdh, resolution 2.20Å" /> | caption="2hdh, resolution 2.20Å" /> | ||
'''BIOCHEMICAL CHARACTERIZATION AND STRUCTURE DETERMINATION OF HUMAN HEART SHORT CHAIN L-3-HYDROXYACYL COA DEHYDROGENASE PROVIDE INSIGHT INTO CATALYTIC MECHANISM'''<br /> | '''BIOCHEMICAL CHARACTERIZATION AND STRUCTURE DETERMINATION OF HUMAN HEART SHORT CHAIN L-3-HYDROXYACYL COA DEHYDROGENASE PROVIDE INSIGHT INTO CATALYTIC MECHANISM'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Human heart short chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) | + | Human heart short chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) catalyzes the oxidation of the hydroxyl group of L-3-hydroxyacyl-CoA to a keto group, concomitant with the reduction of NAD+ to NADH, as part of the beta-oxidation pathway. The homodimeric enzyme has been overexpressed in Escherichia coli, purified to homogeneity, and studied using biochemical and crystallographic techniques. The dissociation constants of NAD+ and NADH have been determined over a broad pH range and indicate that SCHAD binds reduced cofactor preferentially. Examination of apparent catalytic constants reveals that SCHAD displays optimal enzymatic activity near neutral pH, with catalytic efficiency diminishing rapidly toward pH extremes. The crystal structure of SCHAD complexed with NAD+ has been solved using multiwavelength anomalous diffraction techniques and a selenomethionine-substituted analogue of the enzyme. The subunit structure is comprised of two domains. The first domain is similar to other alpha/beta dinucleotide folds but includes an unusual helix-turn-helix motif which extends from the central beta-sheet. The second, or C-terminal, domain is primarily alpha-helical and mediates subunit dimerization and, presumably, L-3-hydroxyacyl-CoA binding. Molecular modeling studies in which L-3-hydroxybutyryl-CoA was docked into the enzyme-NAD+ complex suggest that His 158 serves as a general base, abstracting a proton from the 3-OH group of the substrate. Furthermore, the ability of His 158 to perform such a function may be enhanced by an electrostatic interaction with Glu 170, consistent with previous biochemical observations. These studies provide further understanding of the molecular basis of several inherited metabolic disease states correlated with L-3-hydroxyacyl-CoA dehydrogenase deficiencies. |
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2HDH 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 NAD as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/3-hydroxyacyl-CoA_dehydrogenase 3-hydroxyacyl-CoA dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.35 1.1.1.35] Full crystallographic information is available from [http:// | + | 2HDH 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=NAD:'>NAD</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/3-hydroxyacyl-CoA_dehydrogenase 3-hydroxyacyl-CoA dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.35 1.1.1.35] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HDH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Banaszak, L | + | [[Category: Banaszak, L J.]] |
| - | [[Category: Barycki, J | + | [[Category: Barycki, J J.]] |
| - | [[Category: Bratt, J | + | [[Category: Bratt, J M.]] |
[[Category: NAD]] | [[Category: NAD]] | ||
[[Category: beta oxidation]] | [[Category: beta oxidation]] | ||
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[[Category: schad]] | [[Category: schad]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:40:41 2008'' |
Revision as of 15:40, 21 February 2008
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BIOCHEMICAL CHARACTERIZATION AND STRUCTURE DETERMINATION OF HUMAN HEART SHORT CHAIN L-3-HYDROXYACYL COA DEHYDROGENASE PROVIDE INSIGHT INTO CATALYTIC MECHANISM
Contents |
Overview
Human heart short chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) catalyzes the oxidation of the hydroxyl group of L-3-hydroxyacyl-CoA to a keto group, concomitant with the reduction of NAD+ to NADH, as part of the beta-oxidation pathway. The homodimeric enzyme has been overexpressed in Escherichia coli, purified to homogeneity, and studied using biochemical and crystallographic techniques. The dissociation constants of NAD+ and NADH have been determined over a broad pH range and indicate that SCHAD binds reduced cofactor preferentially. Examination of apparent catalytic constants reveals that SCHAD displays optimal enzymatic activity near neutral pH, with catalytic efficiency diminishing rapidly toward pH extremes. The crystal structure of SCHAD complexed with NAD+ has been solved using multiwavelength anomalous diffraction techniques and a selenomethionine-substituted analogue of the enzyme. The subunit structure is comprised of two domains. The first domain is similar to other alpha/beta dinucleotide folds but includes an unusual helix-turn-helix motif which extends from the central beta-sheet. The second, or C-terminal, domain is primarily alpha-helical and mediates subunit dimerization and, presumably, L-3-hydroxyacyl-CoA binding. Molecular modeling studies in which L-3-hydroxybutyryl-CoA was docked into the enzyme-NAD+ complex suggest that His 158 serves as a general base, abstracting a proton from the 3-OH group of the substrate. Furthermore, the ability of His 158 to perform such a function may be enhanced by an electrostatic interaction with Glu 170, consistent with previous biochemical observations. These studies provide further understanding of the molecular basis of several inherited metabolic disease states correlated with L-3-hydroxyacyl-CoA dehydrogenase deficiencies.
Disease
Known diseases associated with this structure: 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency OMIM:[300256], 3-hydroxyacyl-CoA dehydrogenase deficiency OMIM:[601609], Hyperinsulinemic hypoglycemia, familial, 4 OMIM:[601609]
About this Structure
2HDH is a Single protein structure of sequence from Homo sapiens with as ligand. Active as 3-hydroxyacyl-CoA dehydrogenase, with EC number 1.1.1.35 Full crystallographic information is available from OCA.
Reference
Biochemical characterization and crystal structure determination of human heart short chain L-3-hydroxyacyl-CoA dehydrogenase provide insights into catalytic mechanism., Barycki JJ, O'Brien LK, Bratt JM, Zhang R, Sanishvili R, Strauss AW, Banaszak LJ, Biochemistry. 1999 May 4;38(18):5786-98. PMID:10231530
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