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1k8z
From Proteopedia
(New page: 200px<br /><applet load="1k8z" size="450" color="white" frame="true" align="right" spinBox="true" caption="1k8z, resolution 1.70Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1k8z.jpg|left|200px]]<br /><applet load="1k8z" size=" | + | [[Image:1k8z.jpg|left|200px]]<br /><applet load="1k8z" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1k8z, resolution 1.70Å" /> | caption="1k8z, resolution 1.70Å" /> | ||
'''CRYSTAL STRUCTURE OF THE TRYPTOPHAN SYNTHASE BETA-SER178PRO MUTANT COMPLEXED WITH N-[1H-INDOL-3-YL-ACETYL]GLYCINE ACID'''<br /> | '''CRYSTAL STRUCTURE OF THE TRYPTOPHAN SYNTHASE BETA-SER178PRO MUTANT COMPLEXED WITH N-[1H-INDOL-3-YL-ACETYL]GLYCINE ACID'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The catalytic activity of the pyridoxal 5'-phosphate-dependent tryptophan | + | The catalytic activity of the pyridoxal 5'-phosphate-dependent tryptophan synthase alpha(2)beta(2) complex is allosterically regulated. The hydrogen bond between the helix betaH6 residue betaSer(178) and the loop alphaL6 residue Gly(181) was shown to be critical in ligand-induced intersubunit signaling, with the alpha-beta communication being completely lost in the mutant betaSer(178) --> Pro (Marabotti, A., De Biase, D., Tramonti, A., Bettati, S., and Mozzarelli, A. (2001) J. Biol. Chem. 276, 17747-17753). The structural basis of the impaired allosteric regulation was investigated by determining the crystal structures of the mutant betaSer(178) --> Pro in the absence and presence of the alpha-subunit ligands indole-3-acetylglycine and glycerol 3-phosphate. The mutation causes local and distant conformational changes especially in the beta-subunit. The ligand-free structure exhibits larger differences at the N-terminal part of helix betaH6, whereas the enzyme ligand complexes show differences at the C-terminal side. In contrast to the wild-type enzyme loop alphaL6 remains in an open conformation even in the presence of alpha-ligands. This effects the equilibrium between active and inactive conformations of the alpha-active site, altering k(cat) and K(m), and forms the structural basis for the missing allosteric communication between the alpha- and beta-subunits. |
==About this Structure== | ==About this Structure== | ||
| - | 1K8Z is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with NA, IAG and PLP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Tryptophan_synthase Tryptophan synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.20 4.2.1.20] Full crystallographic information is available from [http:// | + | 1K8Z is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=IAG:'>IAG</scene> and <scene name='pdbligand=PLP:'>PLP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Tryptophan_synthase Tryptophan synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.20 4.2.1.20] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K8Z OCA]. |
==Reference== | ==Reference== | ||
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[[Category: tryptophan biosynthesis]] | [[Category: tryptophan biosynthesis]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:31:25 2008'' |
Revision as of 11:31, 21 February 2008
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CRYSTAL STRUCTURE OF THE TRYPTOPHAN SYNTHASE BETA-SER178PRO MUTANT COMPLEXED WITH N-[1H-INDOL-3-YL-ACETYL]GLYCINE ACID
Overview
The catalytic activity of the pyridoxal 5'-phosphate-dependent tryptophan synthase alpha(2)beta(2) complex is allosterically regulated. The hydrogen bond between the helix betaH6 residue betaSer(178) and the loop alphaL6 residue Gly(181) was shown to be critical in ligand-induced intersubunit signaling, with the alpha-beta communication being completely lost in the mutant betaSer(178) --> Pro (Marabotti, A., De Biase, D., Tramonti, A., Bettati, S., and Mozzarelli, A. (2001) J. Biol. Chem. 276, 17747-17753). The structural basis of the impaired allosteric regulation was investigated by determining the crystal structures of the mutant betaSer(178) --> Pro in the absence and presence of the alpha-subunit ligands indole-3-acetylglycine and glycerol 3-phosphate. The mutation causes local and distant conformational changes especially in the beta-subunit. The ligand-free structure exhibits larger differences at the N-terminal part of helix betaH6, whereas the enzyme ligand complexes show differences at the C-terminal side. In contrast to the wild-type enzyme loop alphaL6 remains in an open conformation even in the presence of alpha-ligands. This effects the equilibrium between active and inactive conformations of the alpha-active site, altering k(cat) and K(m), and forms the structural basis for the missing allosteric communication between the alpha- and beta-subunits.
About this Structure
1K8Z is a Protein complex structure of sequences from Salmonella typhimurium with , and as ligands. Active as Tryptophan synthase, with EC number 4.2.1.20 Full crystallographic information is available from OCA.
Reference
Crystal structure of the beta Ser178--> Pro mutant of tryptophan synthase. A "knock-out" allosteric enzyme., Weyand M, Schlichting I, Herde P, Marabotti A, Mozzarelli A, J Biol Chem. 2002 Mar 22;277(12):10653-60. Epub 2001 Dec 26. PMID:11756454
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