3brk
From Proteopedia
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'''Crystal Structure of ADP-Glucose Pyrophosphorylase from Agrobacterium tumefaciens''' | '''Crystal Structure of ADP-Glucose Pyrophosphorylase from Agrobacterium tumefaciens''' | ||
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| + | ==Overview== | ||
| + | ADP-glucose pyrophosphorylase (ADPGlc PPase) catalyzes the conversion of glucose 1-phosphate and ATP to ADP-glucose and pyrophosphate. As a key step in glucan synthesis, the ADPGlc PPases are highly regulated by allosteric activators and inhibitors in accord with the carbon metabolism pathways of the organism. Crystals of Agrobacterium tumefaciens ADPGlc PPase were obtained using lithium sulfate as a precipitant. A complete anomalous selenomethionyl derivative X-ray diffraction data set was collected with unit cell dimensions a = 85.38 A, b = 93.79 A, and c = 140.29 A (alpha = beta = gamma = 90 degrees ) and space group I 222. The A. tumefaciens ADPGlc PPase model was refined to 2.1 A with an R factor = 22% and R free = 26.6%. The model consists of two domains: an N-terminal alphabetaalpha sandwich and a C-terminal parallel beta-helix. ATP and glucose 1-phosphate were successfully modeled in the proposed active site, and site-directed mutagenesis of conserved glycines in this region (G20, G21, and G23) resulted in substantial loss of activity. The interface between the N- and the C-terminal domains harbors a strong sulfate-binding site, and kinetic studies revealed that sulfate is a competitive inhibitor for the allosteric activator fructose 6-phosphate. These results suggest that the interface between the N- and C-terminal domains binds the allosteric regulator, and fructose 6-phosphate was modeled into this region. The A. tumefaciens ADPGlc PPase/fructose 6-phosphate structural model along with sequence alignment analysis was used to design mutagenesis experiments to expand the activator specificity to include fructose 1,6-bisphosphate. The H379R and H379K enzymes were found to be activated by fructose 1,6-bisphosphate. | ||
==About this Structure== | ==About this Structure== | ||
3BRK is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Agrobacterium_tumefaciens Agrobacterium tumefaciens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BRK OCA]. | 3BRK is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Agrobacterium_tumefaciens Agrobacterium tumefaciens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BRK OCA]. | ||
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| + | ==Reference== | ||
| + | Structural analysis of ADP-glucose pyrophosphorylase from the bacterium Agrobacterium tumefaciens., Cupp-Vickery JR, Igarashi RY, Perez M, Poland M, Meyer CR, Biochemistry. 2008 Apr 15;47(15):4439-51. Epub 2008 Mar 21. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18355040 18355040] | ||
[[Category: Agrobacterium tumefaciens]] | [[Category: Agrobacterium tumefaciens]] | ||
[[Category: Glucose-1-phosphate adenylyltransferase]] | [[Category: Glucose-1-phosphate adenylyltransferase]] | ||
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[[Category: Structure-function relationship]] | [[Category: Structure-function relationship]] | ||
[[Category: Transferase]] | [[Category: Transferase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu May 22 22:35:31 2008'' |
Revision as of 19:35, 22 May 2008
Crystal Structure of ADP-Glucose Pyrophosphorylase from Agrobacterium tumefaciens
Overview
ADP-glucose pyrophosphorylase (ADPGlc PPase) catalyzes the conversion of glucose 1-phosphate and ATP to ADP-glucose and pyrophosphate. As a key step in glucan synthesis, the ADPGlc PPases are highly regulated by allosteric activators and inhibitors in accord with the carbon metabolism pathways of the organism. Crystals of Agrobacterium tumefaciens ADPGlc PPase were obtained using lithium sulfate as a precipitant. A complete anomalous selenomethionyl derivative X-ray diffraction data set was collected with unit cell dimensions a = 85.38 A, b = 93.79 A, and c = 140.29 A (alpha = beta = gamma = 90 degrees ) and space group I 222. The A. tumefaciens ADPGlc PPase model was refined to 2.1 A with an R factor = 22% and R free = 26.6%. The model consists of two domains: an N-terminal alphabetaalpha sandwich and a C-terminal parallel beta-helix. ATP and glucose 1-phosphate were successfully modeled in the proposed active site, and site-directed mutagenesis of conserved glycines in this region (G20, G21, and G23) resulted in substantial loss of activity. The interface between the N- and the C-terminal domains harbors a strong sulfate-binding site, and kinetic studies revealed that sulfate is a competitive inhibitor for the allosteric activator fructose 6-phosphate. These results suggest that the interface between the N- and C-terminal domains binds the allosteric regulator, and fructose 6-phosphate was modeled into this region. The A. tumefaciens ADPGlc PPase/fructose 6-phosphate structural model along with sequence alignment analysis was used to design mutagenesis experiments to expand the activator specificity to include fructose 1,6-bisphosphate. The H379R and H379K enzymes were found to be activated by fructose 1,6-bisphosphate.
About this Structure
3BRK is a Single protein structure of sequence from Agrobacterium tumefaciens. Full crystallographic information is available from OCA.
Reference
Structural analysis of ADP-glucose pyrophosphorylase from the bacterium Agrobacterium tumefaciens., Cupp-Vickery JR, Igarashi RY, Perez M, Poland M, Meyer CR, Biochemistry. 2008 Apr 15;47(15):4439-51. Epub 2008 Mar 21. PMID:18355040 Page seeded by OCA on Thu May 22 22:35:31 2008
Categories: Agrobacterium tumefaciens | Glucose-1-phosphate adenylyltransferase | Single protein | Cupp-Vickery, J. | Igarashi, R. | Meyer, C. | Adp-glucose pyrophosphorylase | Agrobacterium tumefacien | Allostery | Glycogen biosynthesis | Kinetic | Nucleotidyltransferase | Site-directed mutagenesis | Structure-function relationship | Transferase
