1k7f
From Proteopedia
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'''CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH N-[1H-INDOL-3-YL-ACETYL]VALINE ACID''' | '''CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH N-[1H-INDOL-3-YL-ACETYL]VALINE ACID''' | ||
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[[Category: Schlichting, I.]] | [[Category: Schlichting, I.]] | ||
[[Category: Weyand, M.]] | [[Category: Weyand, M.]] | ||
| - | [[Category: | + | [[Category: Carbon-oxygen lyase]] |
| - | [[Category: | + | [[Category: Pyridoxal phosphate]] |
| - | [[Category: | + | [[Category: Tryptophan biosynthesis]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:24:03 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 19:24, 2 May 2008
CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH N-[1H-INDOL-3-YL-ACETYL]VALINE ACID
Overview
Tryptophan synthase is a bifunctional alpha(2)beta(2) complex catalyzing the last two steps of l-tryptophan biosynthesis. The natural substrates of the alpha-subunit indole- 3-glycerolphosphate and glyceraldehyde-3-phosphate, and the substrate analogs indole-3-propanolphosphate and dl-alpha-glycerol-3-phosphate are allosteric effectors of the beta-subunit activity. It has been shown recently, that the indole-3-acetyl amino acids indole-3-acetylglycine and indole-3-acetyl-l-aspartic acid are both alpha-subunit inhibitors and beta-subunit allosteric effectors, whereas indole-3-acetyl-l-valine is only an alpha-subunit inhibitor (Marabotti, A., Cozzini, P., and Mozzarelli, A. (2000) Biochim. Biophys. Acta 1476, 287-299). The crystal structures of tryptophan synthase complexed with indole-3-acetylglycine and indole-3-acetyl-l-aspartic acid show that both ligands bind to the active site such that the carboxylate moiety is positioned similarly as the phosphate group of the natural substrates. As a consequence, the residues of the alpha-active site that interact with the ligands are the same as observed in the indole 3-glycerolphosphate-enzyme complex. Ligand binding leads to closure of loop alphaL6 of the alpha-subunit, a key structural element of intersubunit communication. This is in keeping with the allosteric role played by these compounds. The structure of the enzyme complex with indole-3-acetyl-l-valine is quite different. Due to the hydrophobic lateral chain, this molecule adopts a new orientation in the alpha-active site. In this case, closure of loop alphaL6 is no longer observed, in agreement with its functioning only as an inhibitor of the alpha-subunit reaction.
About this Structure
1K7F is a Protein complex structure of sequences from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
Crystal structures of a new class of allosteric effectors complexed to tryptophan synthase., Weyand M, Schlichting I, Marabotti A, Mozzarelli A, J Biol Chem. 2002 Mar 22;277(12):10647-52. Epub 2001 Dec 26. PMID:11756456 Page seeded by OCA on Fri May 2 22:24:03 2008
