1hox
From Proteopedia
(New page: 200px<br /> <applet load="1hox" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hox, resolution 2.1Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1hox.gif|left|200px]]<br /> | + | [[Image:1hox.gif|left|200px]]<br /><applet load="1hox" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1hox" size=" | + | |
caption="1hox, resolution 2.1Å" /> | caption="1hox, resolution 2.1Å" /> | ||
'''CRYSTAL STRUCTURE OF RABBIT PHOSPHOGLUCOSE ISOMERASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE'''<br /> | '''CRYSTAL STRUCTURE OF RABBIT PHOSPHOGLUCOSE ISOMERASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Phosphoglucose isomerase (PGI, EC 5.3.1.9) catalyzes the interconversion | + | Phosphoglucose isomerase (PGI, EC 5.3.1.9) catalyzes the interconversion of D-glucose 6-phosphate (G6P) and D-fructose 6-phosphate (F6P) and plays important roles in glycolysis and gluconeogenesis. Biochemical characterization of the enzyme has led to a proposed multistep catalytic mechanism. First, the enzyme catalyzes ring opening to yield the open chain form of the substrate. Then isomerization proceeds via proton transfer between C2 and C1 of a cis-enediol(ate) intermediate to yield the open chain form of the product. Catalysis proceeds in both the G6P to F6P and F6P to G6P directions, so both G6P and F6P are substrates. X-ray crystal structure analysis of rabbit and bacterial PGI has previously identified the location of the enzyme active site, and a recent crystal structure of rabbit PGI identified Glu357 as a candidate functional group for transferring the proton. However, it was not clear which active site amino acid residues catalyze the ring opening step. In this paper, we report the X-ray crystal structure of rabbit PGI complexed with the cyclic form of its substrate, D-fructose 6-phosphate, at 2.1 A resolution. The location of the substrate relative to the side chains of His388 suggest that His388 promotes ring opening by protonating the ring oxygen. Glu216 helps to position His388, and a water molecule that is held in position by Lys518 and Thr214 accepts a proton from the hydroxyl group at C2. Comparison to a structure of rabbit PGI with 5PAA bound indicates that ring opening is followed by loss of the protonated water molecule and conformational changes in the substrate and the protein so that a helix containing amino acids 513-520 moves in toward the substrate to form additional hydrogen bonds with the substrate. |
==About this Structure== | ==About this Structure== | ||
| - | 1HOX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus] with F6P as [http://en.wikipedia.org/wiki/ligand ligand]. The following page contains interesting information on the relation of 1HOX with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb50_1.html The Glycolytic Enzymes]]. Active as [http://en.wikipedia.org/wiki/Glucose-6-phosphate_isomerase Glucose-6-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.9 5.3.1.9] Full crystallographic information is available from [http:// | + | 1HOX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus] with <scene name='pdbligand=F6P:'>F6P</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. The following page contains interesting information on the relation of 1HOX with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb50_1.html The Glycolytic Enzymes]]. Active as [http://en.wikipedia.org/wiki/Glucose-6-phosphate_isomerase Glucose-6-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.9 5.3.1.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HOX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: The Glycolytic Enzymes]] | [[Category: The Glycolytic Enzymes]] | ||
| - | [[Category: Chang, K | + | [[Category: Chang, K Z.]] |
| - | [[Category: Jeffrey, C | + | [[Category: Jeffrey, C J.]] |
| - | [[Category: Lee, J | + | [[Category: Lee, J H.]] |
[[Category: Patel, V.]] | [[Category: Patel, V.]] | ||
[[Category: F6P]] | [[Category: F6P]] | ||
[[Category: emzyme -substrate complex]] | [[Category: emzyme -substrate complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:03:22 2008'' |
Revision as of 11:03, 21 February 2008
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CRYSTAL STRUCTURE OF RABBIT PHOSPHOGLUCOSE ISOMERASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE
Overview
Phosphoglucose isomerase (PGI, EC 5.3.1.9) catalyzes the interconversion of D-glucose 6-phosphate (G6P) and D-fructose 6-phosphate (F6P) and plays important roles in glycolysis and gluconeogenesis. Biochemical characterization of the enzyme has led to a proposed multistep catalytic mechanism. First, the enzyme catalyzes ring opening to yield the open chain form of the substrate. Then isomerization proceeds via proton transfer between C2 and C1 of a cis-enediol(ate) intermediate to yield the open chain form of the product. Catalysis proceeds in both the G6P to F6P and F6P to G6P directions, so both G6P and F6P are substrates. X-ray crystal structure analysis of rabbit and bacterial PGI has previously identified the location of the enzyme active site, and a recent crystal structure of rabbit PGI identified Glu357 as a candidate functional group for transferring the proton. However, it was not clear which active site amino acid residues catalyze the ring opening step. In this paper, we report the X-ray crystal structure of rabbit PGI complexed with the cyclic form of its substrate, D-fructose 6-phosphate, at 2.1 A resolution. The location of the substrate relative to the side chains of His388 suggest that His388 promotes ring opening by protonating the ring oxygen. Glu216 helps to position His388, and a water molecule that is held in position by Lys518 and Thr214 accepts a proton from the hydroxyl group at C2. Comparison to a structure of rabbit PGI with 5PAA bound indicates that ring opening is followed by loss of the protonated water molecule and conformational changes in the substrate and the protein so that a helix containing amino acids 513-520 moves in toward the substrate to form additional hydrogen bonds with the substrate.
About this Structure
1HOX is a Single protein structure of sequence from Oryctolagus cuniculus with as ligand. The following page contains interesting information on the relation of 1HOX with [The Glycolytic Enzymes]. Active as Glucose-6-phosphate isomerase, with EC number 5.3.1.9 Full crystallographic information is available from OCA.
Reference
Crystal structure of rabbit phosphoglucose isomerase complexed with its substrate D-fructose 6-phosphate., Lee JH, Chang KZ, Patel V, Jeffery CJ, Biochemistry. 2001 Jul 3;40(26):7799-805. PMID:11425306
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