1sc6
From Proteopedia
(New page: 200px<br /><applet load="1sc6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1sc6, resolution 2.09Å" /> '''Crystal Structure of...) |
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| - | [[Image:1sc6.gif|left|200px]]<br /><applet load="1sc6" size=" | + | [[Image:1sc6.gif|left|200px]]<br /><applet load="1sc6" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1sc6, resolution 2.09Å" /> | caption="1sc6, resolution 2.09Å" /> | ||
'''Crystal Structure of W139G D-3-Phosphoglycerate dehydrogenase complexed with NAD+'''<br /> | '''Crystal Structure of W139G D-3-Phosphoglycerate dehydrogenase complexed with NAD+'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Phosphoglycerate dehydrogenase (PGDH) catalyzes the first step in the | + | Phosphoglycerate dehydrogenase (PGDH) catalyzes the first step in the serine biosynthetic pathway. In lower plants and bacteria, the PGDH reaction is regulated by the end-product of the pathway, serine. The regulation occurs through a V(max) mechanism with serine binding and inhibition occurring in a cooperative manner. The three-dimensional structure of the serine inhibited enzyme, determined by previous work, showed a tetrameric enzyme with 222 symmetry and an unusual overall toroidal appearance. To characterize the allosteric, cooperative effects of serine, we identified W139G PGDH as an enzymatically active mutant responsive to serine but not in a cooperative manner. The position of W139 near a subunit interface and the active site cleft suggested that this residue is a key player in relaying allosteric effects. The 2.09 A crystal structure of W139G-PGDH, determined in the absence of serine, revealed major quaternary and tertiary structural changes. Contrary to the wildtype enzyme where residues encompassing residue 139 formed extensive intersubunit contacts, the corresponding residues in the mutant were conformationally flexible. Within each of the three-domain subunits, one domain has rotated approximately 42 degrees relative to the other two. The resulting quaternary structure is now in a novel conformation creating new subunit-to-subunit contacts and illustrates the unusual flexibility in this V(max) regulated enzyme. Although changes at the regulatory domain interface have implications in other enzymes containing a similar regulatory or ACT domain, the serine binding site in W139G PGDH is essentially unchanged from the wildtype enzyme. The structural and previous biochemical characterization of W139G PGDH suggests that the allosteric regulation of PGDH is mediated not only by changes occurring at the ACT domain interface but also by conformational changes at the interface encompassing residue W139. |
==About this Structure== | ==About this Structure== | ||
| - | 1SC6 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 NAD as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phosphoglycerate_dehydrogenase Phosphoglycerate dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.95 1.1.1.95] Full crystallographic information is available from [http:// | + | 1SC6 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=NAD:'>NAD</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phosphoglycerate_dehydrogenase Phosphoglycerate dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.95 1.1.1.95] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SC6 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Phosphoglycerate dehydrogenase]] | [[Category: Phosphoglycerate dehydrogenase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Banaszak, L | + | [[Category: Banaszak, L J.]] |
| - | [[Category: Bell, J | + | [[Category: Bell, J K.]] |
| - | [[Category: Grant, G | + | [[Category: Grant, G A.]] |
[[Category: NAD]] | [[Category: NAD]] | ||
[[Category: allosteric regulation phosphoglycerate dehydrogenase pgdh]] | [[Category: allosteric regulation phosphoglycerate dehydrogenase pgdh]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:00:08 2008'' |
Revision as of 13:00, 21 February 2008
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Crystal Structure of W139G D-3-Phosphoglycerate dehydrogenase complexed with NAD+
Overview
Phosphoglycerate dehydrogenase (PGDH) catalyzes the first step in the serine biosynthetic pathway. In lower plants and bacteria, the PGDH reaction is regulated by the end-product of the pathway, serine. The regulation occurs through a V(max) mechanism with serine binding and inhibition occurring in a cooperative manner. The three-dimensional structure of the serine inhibited enzyme, determined by previous work, showed a tetrameric enzyme with 222 symmetry and an unusual overall toroidal appearance. To characterize the allosteric, cooperative effects of serine, we identified W139G PGDH as an enzymatically active mutant responsive to serine but not in a cooperative manner. The position of W139 near a subunit interface and the active site cleft suggested that this residue is a key player in relaying allosteric effects. The 2.09 A crystal structure of W139G-PGDH, determined in the absence of serine, revealed major quaternary and tertiary structural changes. Contrary to the wildtype enzyme where residues encompassing residue 139 formed extensive intersubunit contacts, the corresponding residues in the mutant were conformationally flexible. Within each of the three-domain subunits, one domain has rotated approximately 42 degrees relative to the other two. The resulting quaternary structure is now in a novel conformation creating new subunit-to-subunit contacts and illustrates the unusual flexibility in this V(max) regulated enzyme. Although changes at the regulatory domain interface have implications in other enzymes containing a similar regulatory or ACT domain, the serine binding site in W139G PGDH is essentially unchanged from the wildtype enzyme. The structural and previous biochemical characterization of W139G PGDH suggests that the allosteric regulation of PGDH is mediated not only by changes occurring at the ACT domain interface but also by conformational changes at the interface encompassing residue W139.
About this Structure
1SC6 is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Phosphoglycerate dehydrogenase, with EC number 1.1.1.95 Full crystallographic information is available from OCA.
Reference
Multiconformational states in phosphoglycerate dehydrogenase., Bell JK, Grant GA, Banaszak LJ, Biochemistry. 2004 Mar 30;43(12):3450-8. PMID:15035616
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