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| {{STRUCTURE_1gdh| PDB=1gdh | SCENE= }} | | {{STRUCTURE_1gdh| PDB=1gdh | SCENE= }} |
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| '''CRYSTAL STRUCTURE OF A NAD-DEPENDENT D-GLYCERATE DEHYDROGENASE AT 2.4 ANGSTROMS RESOLUTION'''
| | ===CRYSTAL STRUCTURE OF A NAD-DEPENDENT D-GLYCERATE DEHYDROGENASE AT 2.4 ANGSTROMS RESOLUTION=== |
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| ==Overview==
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| D-Glycerate dehydrogenase (GDH) catalyzes the NADH-linked reduction of hydroxypyruvate to D-glycerate. GDH is a member of a family of NAD-dependent dehydrogenases that is characterized by a specificity for the D-isomer of the hydroxyacid substrate. The crystal structure of the apoenzyme form of GDH from Hyphomicrobium methylovorum has been determined by the method of isomorphous replacement and refined at 2.4 A resolution using a restrained least-squares method. The crystallographic R-factor is 19.4% for all 24,553 measured reflections between 10.0 and 2.4 A resolution. The GDH molecule is a symmetrical dimer composed of subunits of molecular mass 38,000, and shares significant structural homology with another NAD-dependent enzyme, formate dehydrogenase. The GDH subunit consists of two structurally similar domains that are approximately related to each other by 2-fold symmetry. The domains are separated by a deep cleft that forms the putative NAD and substrate binding sites. One of the domains has been identified as the NAD-binding domain based on its close structural similarity to the NAD-binding domains of other NAD-dependent dehydrogenases. The topology of the second domain is different from that found in the various catalytic domains of other dehydrogenases. A model of a ternary complex of GDH has been built in which putative catalytic residues are identified based on sequence homology between the D-isomer specific dehydrogenases. A structural comparison between GDH and L-lactate dehydrogenase indicates a convergence of active site residues and geometries for these two enzymes. The reactions catalyzed are chemically equivalent but of opposing stereospecificity. A hypothesis is presented to explain how the two enzymes may exploit the same coenzyme stereochemistry and a similar spatial arrangement of catalytic residues to carry out reactions that proceed to opposite enantiomers.
| | The line below this paragraph, {{ABSTRACT_PUBMED_8120891}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 8120891 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_8120891}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Goldberg, J D.]] | | [[Category: Goldberg, J D.]] |
| [[Category: Yoshida, T.]] | | [[Category: Yoshida, T.]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:26:41 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 05:08:09 2008'' |