1kfk
From Proteopedia
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|PDB= 1kfk |SIZE=350|CAPTION= <scene name='initialview01'>1kfk</scene>, resolution 2.40Å | |PDB= 1kfk |SIZE=350|CAPTION= <scene name='initialview01'>1kfk</scene>, resolution 2.40Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> and <scene name='pdbligand=PLP:PYRIDOXAL-5 | + | |LIGAND= <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> and <scene name='pdbligand=PLP:PYRIDOXAL-5'-PHOSPHATE'>PLP</scene> |
|ACTIVITY= [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] | |ACTIVITY= [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] | ||
|GENE= | |GENE= | ||
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[[Category: tryptophan biosynthesis]] | [[Category: tryptophan biosynthesis]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 23 12:28:53 2008'' |
Revision as of 10:28, 23 March 2008
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| , resolution 2.40Å | |||||||
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| Ligands: | and | ||||||
| Activity: | Tryptophan synthase, with EC number 4.2.1.20 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of Tryptophan Synthase From Salmonella Typhimurium
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
1KFK is a Protein complex structure of sequences from Salmonella typhimurium and Salmonella typhimurium lt2. 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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