1kfb
From Proteopedia
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'''CRYSTAL STRUCTURE OF ALPHAT183V MUTANT OF TRYPTOPHAN SYNTHASE FROM SALMONELLA TYPHIMURIUM WITH Indole Glycerol Phosphate''' | '''CRYSTAL STRUCTURE OF ALPHAT183V MUTANT OF TRYPTOPHAN SYNTHASE FROM SALMONELLA TYPHIMURIUM WITH Indole Glycerol Phosphate''' | ||
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[[Category: Siedel, R.]] | [[Category: Siedel, R.]] | ||
[[Category: Weyand, M.]] | [[Category: Weyand, M.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:40:32 2008'' | |
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Revision as of 19:40, 2 May 2008
CRYSTAL STRUCTURE OF ALPHAT183V MUTANT OF TRYPTOPHAN SYNTHASE FROM SALMONELLA TYPHIMURIUM WITH Indole Glycerol Phosphate
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
1KFB is a Protein complex structure of sequences from Salmonella typhimurium. 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 Page seeded by OCA on Fri May 2 22:40:32 2008
