1amr: Difference between revisions

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X-RAY CRYSTALLOGRAPHIC STUDY OF PYRIDOXAMINE 5'-PHOSPHATE-TYPE ASPARTATE AMINOTRANSFERASES FROM ESCHERICHIA COLI IN THREE FORMS

OverviewOverview

The three-dimensional structures of pyridoxamine 5'-phosphate-type aspartate aminotransferase from Escherichia coli and its complexes with maleate and glutarate have been determined by X-ray crystallography at 2.2, 2.1, and 2.7 A resolution, respectively. The enzyme is a dimeric form comprising two identical subunits, each of which is divided into one large and one small domain. The complex with maleate showed that substrate (or inhibitor) binding induced a large conformational change from the "open" to the "closed" form, resulting in closure of the active site by the small domain movement, as was observed in the pyridoxal 5'-phosphate-type enzyme. In the open form, three hydrophobic residues (hydrophobic plug) at the entrance of the active site are exposed to solvent. Maleate binding make the active site more hydrophobic by charge compensation and release of water molecules, facilitating the movement of the hydrophobic plug into the active site pocket to induce a large conformational change in the enzyme. Maleate is fixed rigidly in the active site pocket by extensive salt bridges and a hydrogen bonding network, guaranteeing the stereo-specificity of the catalysis and giving a Michaelis complex model. Contrary to our expectation, the glutarate complex was in the open form, suggesting that the equilibrium between the open and closed forms lies far toward the open form in solution. The water molecules located in the active site pocket were almost completely conserved between Escherichia coli and chicken mitochondrial aspartate aminotransferase with the same type of cofactor and the same conformation.

About this StructureAbout this Structure

1AMR is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.

ReferenceReference

X-ray crystallographic study of pyridoxamine 5'-phosphate-type aspartate aminotransferases from Escherichia coli in three forms., Miyahara I, Hirotsu K, Hayashi H, Kagamiyama H, J Biochem. 1994 Nov;116(5):1001-12. PMID:7896726

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-[[Image:1amr.jpg|left|200px]]<br /><applet load="1amr" size="450" color="white" frame="true" align="right" spinBox="true"
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 caption="1amr, resolution 2.1&Aring;" />
 '''X-RAY CRYSTALLOGRAPHIC STUDY OF PYRIDOXAMINE 5'-PHOSPHATE-TYPE ASPARTATE AMINOTRANSFERASES FROM ESCHERICHIA COLI IN THREE FORMS'''<br />
 ==Overview==
-The three-dimensional structures of pyridoxamine 5'-phosphate-type, aspartate aminotransferase from Escherichia coli and its complexes with, maleate and glutarate have been determined by X-ray crystallography at, 2.2, 2.1, and 2.7 A resolution, respectively. The enzyme is a dimeric form, comprising two identical subunits, each of which is divided into one large, and one small domain. The complex with maleate showed that substrate (or, inhibitor) binding induced a large conformational change from the "open", to the "closed" form, resulting in closure of the active site by the small, domain movement, as was observed in the pyridoxal 5'-phosphate-type, enzyme. In the open form, three hydrophobic residues (hydrophobic plug) at, the entrance of the active site are exposed to solvent. Maleate binding, make the active site more hydrophobic by charge compensation and release, of water molecules, facilitating the movement of the hydrophobic plug into, the active site pocket to induce a large conformational change in the, enzyme. Maleate is fixed rigidly in the active site pocket by extensive, salt bridges and a hydrogen bonding network, guaranteeing the, stereo-specificity of the catalysis and giving a Michaelis complex model., Contrary to our expectation, the glutarate complex was in the open form, suggesting that the equilibrium between the open and closed forms lies far, toward the open form in solution. The water molecules located in the, active site pocket were almost completely conserved between Escherichia, coli and chicken mitochondrial aspartate aminotransferase with the same, type of cofactor and the same conformation.
+The three-dimensional structures of pyridoxamine 5'-phosphate-type aspartate aminotransferase from Escherichia coli and its complexes with maleate and glutarate have been determined by X-ray crystallography at 2.2, 2.1, and 2.7 A resolution, respectively. The enzyme is a dimeric form comprising two identical subunits, each of which is divided into one large and one small domain. The complex with maleate showed that substrate (or inhibitor) binding induced a large conformational change from the "open" to the "closed" form, resulting in closure of the active site by the small domain movement, as was observed in the pyridoxal 5'-phosphate-type enzyme. In the open form, three hydrophobic residues (hydrophobic plug) at the entrance of the active site are exposed to solvent. Maleate binding make the active site more hydrophobic by charge compensation and release of water molecules, facilitating the movement of the hydrophobic plug into the active site pocket to induce a large conformational change in the enzyme. Maleate is fixed rigidly in the active site pocket by extensive salt bridges and a hydrogen bonding network, guaranteeing the stereo-specificity of the catalysis and giving a Michaelis complex model. Contrary to our expectation, the glutarate complex was in the open form, suggesting that the equilibrium between the open and closed forms lies far toward the open form in solution. The water molecules located in the active site pocket were almost completely conserved between Escherichia coli and chicken mitochondrial aspartate aminotransferase with the same type of cofactor and the same conformation.
 ==About this Structure==
-AMR 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 PMP and MAE as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aspartate_transaminase Aspartate transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.1 2.6.1.1] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1AMR OCA].
+AMR 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=PMP:'>PMP</scene> and <scene name='pdbligand=MAE:'>MAE</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aspartate_transaminase Aspartate transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.1 2.6.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AMR OCA].
 ==Reference==
-X-ray crystallographic study of pyridoxamine 5'-phosphate-type aspartate aminotransferases from Escherichia coli in three forms., Miyahara I, Hirotsu K, Hayashi H, Kagamiyama H, J Biochem (Tokyo). 1994 Nov;116(5):1001-12. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=7896726 7896726]
+X-ray crystallographic study of pyridoxamine 5'-phosphate-type aspartate aminotransferases from Escherichia coli in three forms., Miyahara I, Hirotsu K, Hayashi H, Kagamiyama H, J Biochem. 1994 Nov;116(5):1001-12. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=7896726 7896726]
 [[Category: Aspartate transaminase]]
 [[Category: Escherichia coli]]
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 [[Category: transferase(aminotransferase)]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 10:58:12 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:46:14 2008''