1kfj
From Proteopedia
(New page: 200px<br /><applet load="1kfj" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kfj, resolution 1.80Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1kfj.jpg|left|200px]]<br /><applet load="1kfj" size=" | + | [[Image:1kfj.jpg|left|200px]]<br /><applet load="1kfj" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1kfj, resolution 1.80Å" /> | caption="1kfj, resolution 1.80Å" /> | ||
'''CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH L-SERINE'''<br /> | '''CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH L-SERINE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The catalytic activity and substrate channeling of the pyridoxal | + | The catalytic activity and substrate channeling of the pyridoxal 5'-phosphate-dependent tryptophan synthase alpha(2)beta(2) complex is regulated by allosteric interactions that modulate the switching of the enzyme between open, low activity and closed, high activity states during the catalytic cycle. The highly conserved alphaThr183 residue is part of loop alphaL6 and is located next to the alpha-active site and forms part of the alpha-beta subunit interface. The role of the interactions of alphaThr183 in alpha-site catalysis and allosteric regulation was investigated by analyzing the kinetics and crystal structures of the isosteric mutant alphaThr183Val. The mutant displays strongly impaired allosteric alpha-beta communication, and the catalytic activity of the alpha-reaction is reduced one hundred fold, whereas the beta-activity is not affected. The structural work establishes that the basis for the missing inter-subunit signaling is the lack of loop alphaL6 closure even in the presence of the alpha-subunit ligands, 3-indolyl-D-glycerol 3'-phosphate, or 3-indolylpropanol 3'-phosphate. The structural basis for the reduced alpha-activity has its origins in the missing hydrogen bond between alphaThr183 and the catalytic residue, alphaAsp60. |
==About this Structure== | ==About this Structure== | ||
| - | 1KFJ 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 and PLS 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:// | + | 1KFJ 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> and <scene name='pdbligand=PLS:'>PLS</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=1KFJ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Tryptophan synthase]] | [[Category: Tryptophan synthase]] | ||
[[Category: Arac, D.]] | [[Category: Arac, D.]] | ||
| - | [[Category: Dunn, M | + | [[Category: Dunn, M F.]] |
[[Category: Kulik, V.]] | [[Category: Kulik, V.]] | ||
[[Category: Niks, D.]] | [[Category: Niks, D.]] | ||
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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 13:33:37 2008'' |
Revision as of 11:33, 21 February 2008
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CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH L-SERINE
Overview
The catalytic activity and substrate channeling of the pyridoxal 5'-phosphate-dependent tryptophan synthase alpha(2)beta(2) complex is regulated by allosteric interactions that modulate the switching of the enzyme between open, low activity and closed, high activity states during the catalytic cycle. The highly conserved alphaThr183 residue is part of loop alphaL6 and is located next to the alpha-active site and forms part of the alpha-beta subunit interface. The role of the interactions of alphaThr183 in alpha-site catalysis and allosteric regulation was investigated by analyzing the kinetics and crystal structures of the isosteric mutant alphaThr183Val. The mutant displays strongly impaired allosteric alpha-beta communication, and the catalytic activity of the alpha-reaction is reduced one hundred fold, whereas the beta-activity is not affected. The structural work establishes that the basis for the missing inter-subunit signaling is the lack of loop alphaL6 closure even in the presence of the alpha-subunit ligands, 3-indolyl-D-glycerol 3'-phosphate, or 3-indolylpropanol 3'-phosphate. The structural basis for the reduced alpha-activity has its origins in the missing hydrogen bond between alphaThr183 and the catalytic residue, alphaAsp60.
About this Structure
1KFJ 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
On the role of alphaThr183 in the allosteric regulation and catalytic mechanism of tryptophan synthase., Kulik V, Weyand M, Seidel R, Niks D, Arac D, Dunn MF, Schlichting I, J Mol Biol. 2002 Dec 6;324(4):677-90. PMID:12460570
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