1z84: Difference between revisions

Revision as of 17:12, 21 February 2008

X-ray structure of galt-like protein from arabidopsis thaliana at5g18200

OverviewOverview

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 StructureAbout this Structure

1Z84 is a Single protein structure of sequence from Arabidopsis thaliana with , and as ligands. Full crystallographic information is available from OCA.

ReferenceReference

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

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-[[Image:1z84.gif|left|200px]]<br /><applet load="1z84" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1z84.gif|left|200px]]<br /><applet load="1z84" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1z84, resolution 1.83&Aring;" />
 '''X-ray structure of galt-like protein from arabidopsis thaliana at5g18200'''<br />
 ==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).
+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==
-Z84 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, AMP and EDO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1Z84 OCA].
+Z84 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=AMP:'>AMP</scene> and <scene name='pdbligand=EDO:'>EDO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Z84 OCA].
 ==Reference==
@@ Line 13: / Line 13: @@
 [[Category: Arabidopsis thaliana]]
 [[Category: Single protein]]
-[[Category: Bingman, C.A.]]
+[[Category: Bingman, C A.]]
 [[Category: Bitto, E.]]
-[[Category: CESG, Center.for.Eukaryotic.Structural.Genomics.]]
+[[Category: CESG, Center for Eukaryotic Structural Genomics.]]
-[[Category: Jr., G.N.Phillips.]]
+[[Category: Jr., G N.Phillips.]]
-[[Category: Mccoy, J.G.]]
+[[Category: Mccoy, J G.]]
 [[Category: AMP]]
 [[Category: EDO]]
@@ Line 30: / Line 30: @@
 [[Category: zinc]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 07:17:36 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:12:58 2008''