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| - | [[Image:1v7y.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1v7y| PDB=1v7y | SCENE= }} | | {{STRUCTURE_1v7y| PDB=1v7y | SCENE= }} |
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| - | '''Crystal structure of tryptophan synthase alpha-subunit from Escherichia coli at room temperature'''
| + | ===Crystal structure of tryptophan synthase alpha-subunit from Escherichia coli at room temperature=== |
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| - | ==Overview==
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| - | When the tryptophan synthase alpha- and beta(2)-subunits combine to form the alpha(2)beta(2)-complex, the enzymatic activity of each subunit is stimulated by 1-2 orders of magnitude. To elucidate the structural basis of this mutual activation, it is necessary to determine the structures of the alpha- and beta-subunits alone and together with the alpha(2)beta(2)-complex. The crystal structures of the tryptophan synthase alpha(2)beta(2)-complex from Salmonella typhimurium (Stalpha(2)beta(2)-complex) have already been reported. However, the structures of the subunit alone from mesophiles have not yet been determined. The structure of the tryptophan synthase alpha-subunit alone from Escherichia coli (Ecalpha-subunit) was determined by an X-ray crystallographic analysis at 2.3 A, which is the first report on the subunits alone from the mesophiles. The biggest difference between the structures of the Ecalpha-subunit alone and the alpha-subunit in the Stalpha(2)beta(2)-complex (Stalpha-subunit) was as follows. Helix 2' in the Stalpha-subunit, including an active site residue (Asp60), was changed to a flexible loop in the Ecalpha-subunit alone. The conversion of the helix to a loop resulted in the collapse of the correct active site conformation. This region is also an important part for the mutual activation in the Stalpha(2)beta(2)-complex and interaction with the beta-subunit. These results suggest that the formation of helix 2'that is essential for the stimulation of the enzymatic activity of the alpha-subunit is constructed by the induced-fit mode involved in conformational changes upon interaction between the alpha- and beta-subunits. This also confirms the prediction of the conformational changes based on the thermodynamic analysis for the association between the alpha- and beta-subunits.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_15667212}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15667212 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15667212}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Tryptophan]] | | [[Category: Tryptophan]] |
| | [[Category: Tryptophan synthase]] | | [[Category: Tryptophan synthase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 12:11:45 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 13:41:08 2008'' |
Revision as of 10:41, 29 July 2008
Template:STRUCTURE 1v7y
Crystal structure of tryptophan synthase alpha-subunit from Escherichia coli at room temperature
Template:ABSTRACT PUBMED 15667212
About this Structure
1V7Y is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Conformational changes in the alpha-subunit coupled to binding of the beta 2-subunit of tryptophan synthase from Escherichia coli: crystal structure of the tryptophan synthase alpha-subunit alone., Nishio K, Morimoto Y, Ishizuka M, Ogasahara K, Tsukihara T, Yutani K, Biochemistry. 2005 Feb 1;44(4):1184-92. PMID:15667212
Page seeded by OCA on Tue Jul 29 13:41:08 2008
