2h39
From Proteopedia
(New page: 200px<br /><applet load="2h39" size="450" color="white" frame="true" align="right" spinBox="true" caption="2h39, resolution 2.230Å" /> '''Crystal Structure o...) |
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| - | [[Image:2h39.gif|left|200px]]<br /><applet load="2h39" size=" | + | [[Image:2h39.gif|left|200px]]<br /><applet load="2h39" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2h39, resolution 2.230Å" /> | caption="2h39, resolution 2.230Å" /> | ||
'''Crystal Structure of an ADP-Glucose Phosphorylase from Arabidopsis thaliana with bound ADP-Glucose'''<br /> | '''Crystal Structure of an ADP-Glucose Phosphorylase from Arabidopsis thaliana with bound ADP-Glucose'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The X-ray crystal structure of the At5g18200.1 protein has been determined | + | The X-ray crystal structure of the At5g18200.1 protein has been determined to a nominal resolution of 2.30 A. The structure has a histidine triad (HIT)-like fold containing two distinct HIT-like motifs. The sequence of At5g18200.1 indicates a distant family relationship to the Escherichia coli galactose-1-P uridylyltransferase (GalT): the determined structure of the At5g18200.1 protein confirms this relationship. The At5g18200.1 protein does not demonstrate GalT activity but instead catalyzes adenylyl transfer in the reaction of ADP-glucose with various phosphates. The best acceptor among those evaluated is phosphate itself; thus, the At5g18200.1 enzyme appears to be an ADP-glucose phosphorylase. The enzyme catalyzes the exchange of (14)C between ADP-[(14)C]glucose and glucose-1-P in the absence of phosphate. The steady state kinetics of exchange follows the ping-pong bi-bi kinetic mechanism, with a k(cat) of 4.1 s(-)(1) and K(m) values of 1.4 and 83 microM for ADP-[(14)C]glucose and glucose-1-P, respectively, at pH 8.5 and 25 degrees C. The overall reaction of ADP-glucose with phosphate to produce ADP and glucose-1-P follows ping-pong bi-bi steady state kinetics, with a k(cat) of 2.7 s(-)(1) and K(m) values of 6.9 and 90 microM for ADP-glucose and phosphate, respectively, at pH 8.5 and 25 degrees C. The kinetics are consistent with a double-displacement mechanism that involves a covalent adenylyl-enzyme intermediate. The X-ray crystal structure of this intermediate was determined to 1.83 A resolution and shows the AMP group bonded to His(186). The value of K(eq) in the direction of ADP and glucose-1-P formation is 5.0 at pH 7.0 and 25 degrees C in the absence of a divalent metal ion, and it is 40 in the presence of 1 mM MgCl(2). |
==About this Structure== | ==About this Structure== | ||
| - | 2H39 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana] with ZN, CL and ADQ as [http://en.wikipedia.org/wiki/ligands ligands]. This structure | + | 2H39 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=ADQ:'>ADQ</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 2GDK. Active as [http://en.wikipedia.org/wiki/UDP-glucose--hexose-1-phosphate_uridylyltransferase UDP-glucose--hexose-1-phosphate uridylyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.12 2.7.7.12] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2H39 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: UDP-glucose--hexose-1-phosphate uridylyltransferase]] | [[Category: UDP-glucose--hexose-1-phosphate uridylyltransferase]] | ||
| - | [[Category: Bingman, C | + | [[Category: Bingman, C A.]] |
[[Category: Bitto, E.]] | [[Category: Bitto, E.]] | ||
| - | [[Category: CESG, Center | + | [[Category: CESG, Center for Eukaryotic Structural Genomics.]] |
| - | [[Category: Jr., G | + | [[Category: Jr., G N.Phillips.]] |
| - | [[Category: McCoy, J | + | [[Category: McCoy, J G.]] |
| - | [[Category: Wesenberg, G | + | [[Category: Wesenberg, G E.]] |
[[Category: ADQ]] | [[Category: ADQ]] | ||
[[Category: CL]] | [[Category: CL]] | ||
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[[Category: structural genomics functional follow-up study]] | [[Category: structural genomics functional follow-up study]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:37:47 2008'' |
Revision as of 15:37, 21 February 2008
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Crystal Structure of an ADP-Glucose Phosphorylase from Arabidopsis thaliana with bound ADP-Glucose
Overview
The X-ray crystal structure of the At5g18200.1 protein has been determined to a nominal resolution of 2.30 A. The structure has a histidine triad (HIT)-like fold containing two distinct HIT-like motifs. The sequence of At5g18200.1 indicates a distant family relationship to the Escherichia coli galactose-1-P uridylyltransferase (GalT): the determined structure of the At5g18200.1 protein confirms this relationship. The At5g18200.1 protein does not demonstrate GalT activity but instead catalyzes adenylyl transfer in the reaction of ADP-glucose with various phosphates. The best acceptor among those evaluated is phosphate itself; thus, the At5g18200.1 enzyme appears to be an ADP-glucose phosphorylase. The enzyme catalyzes the exchange of (14)C between ADP-[(14)C]glucose and glucose-1-P in the absence of phosphate. The steady state kinetics of exchange follows the ping-pong bi-bi kinetic mechanism, with a k(cat) of 4.1 s(-)(1) and K(m) values of 1.4 and 83 microM for ADP-[(14)C]glucose and glucose-1-P, respectively, at pH 8.5 and 25 degrees C. The overall reaction of ADP-glucose with phosphate to produce ADP and glucose-1-P follows ping-pong bi-bi steady state kinetics, with a k(cat) of 2.7 s(-)(1) and K(m) values of 6.9 and 90 microM for ADP-glucose and phosphate, respectively, at pH 8.5 and 25 degrees C. The kinetics are consistent with a double-displacement mechanism that involves a covalent adenylyl-enzyme intermediate. The X-ray crystal structure of this intermediate was determined to 1.83 A resolution and shows the AMP group bonded to His(186). The value of K(eq) in the direction of ADP and glucose-1-P formation is 5.0 at pH 7.0 and 25 degrees C in the absence of a divalent metal ion, and it is 40 in the presence of 1 mM MgCl(2).
About this Structure
2H39 is a Single protein structure of sequence from Arabidopsis thaliana with , and as ligands. This structure supersedes the now removed PDB entry 2GDK. Active as UDP-glucose--hexose-1-phosphate uridylyltransferase, with EC number 2.7.7.12 Full crystallographic information is available from OCA.
Reference
Structure and mechanism of an ADP-glucose phosphorylase from Arabidopsis thaliana., McCoy JG, Arabshahi A, Bitto E, Bingman CA, Ruzicka FJ, Frey PA, Phillips GN Jr, Biochemistry. 2006 Mar 14;45(10):3154-62. PMID:16519510
Page seeded by OCA on Thu Feb 21 17:37:47 2008
Categories: Arabidopsis thaliana | Single protein | UDP-glucose--hexose-1-phosphate uridylyltransferase | Bingman, C A. | Bitto, E. | CESG, Center for Eukaryotic Structural Genomics. | Jr., G N.Phillips. | McCoy, J G. | Wesenberg, G E. | ADQ | CL | ZN | Adp-glucose | At5g18200 | Center for eukaryotic structural genomics | Cesg | Galt-like | Protein structure initiative | Psi | Structural genomics functional follow-up study
