1e5x
From Proteopedia
(New page: 200px<br /><applet load="1e5x" size="450" color="white" frame="true" align="right" spinBox="true" caption="1e5x, resolution 2.25Å" /> '''STRUCTURE OF THREONI...) |
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| - | [[Image:1e5x.gif|left|200px]]<br /><applet load="1e5x" size=" | + | [[Image:1e5x.gif|left|200px]]<br /><applet load="1e5x" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1e5x, resolution 2.25Å" /> | caption="1e5x, resolution 2.25Å" /> | ||
'''STRUCTURE OF THREONINE SYNTHASE FROM ARABIDOPSIS THALIANA'''<br /> | '''STRUCTURE OF THREONINE SYNTHASE FROM ARABIDOPSIS THALIANA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Threonine synthase (TS) is a PLP-dependent enzyme that catalyzes the last | + | Threonine synthase (TS) is a PLP-dependent enzyme that catalyzes the last reaction in the synthesis of threonine from aspartate. In plants, the methionine pathway shares the same substrate, O-phospho-L-homoserine (OPH), and TS is activated by S-adenosyl-methionine (SAM), a downstream product of methionine synthesis. This positive allosteric effect triggered by the product of another pathway is specific to plants. The crystal structure of Arabidopsis thaliana apo threonine synthase was solved at 2.25 A resolution from triclinic crystals using MAD data from the selenomethionated protein. The structure reveals a four-domain dimer with a two-stranded beta-sheet arm protruding from one monomer onto the other. This domain swap could form a lever through which the allosteric effect is transmitted. The N-terminal domain (domain 1) has a unique fold and is partially disordered, whereas the structural core (domains 2 and 3) shares the functional domain of PLP enzymes of the same family. It also has similarities with SAM-dependent methyltransferases. Structure comparisons allowed us to propose potential sites for pyridoxal-phosphate and SAM binding on TS; they are close to regions that are disordered in the absence of these molecules. |
==About this Structure== | ==About this Structure== | ||
| - | 1E5X is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Active as [http://en.wikipedia.org/wiki/Threonine_synthase Threonine synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.3.1 4.2.3.1] Full crystallographic information is available from [http:// | + | 1E5X is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Active as [http://en.wikipedia.org/wiki/Threonine_synthase Threonine synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.3.1 4.2.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E5X OCA]. |
==Reference== | ==Reference== | ||
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[[Category: threonine biosynthesis]] | [[Category: threonine biosynthesis]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:24:11 2008'' |
Revision as of 10:24, 21 February 2008
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STRUCTURE OF THREONINE SYNTHASE FROM ARABIDOPSIS THALIANA
Overview
Threonine synthase (TS) is a PLP-dependent enzyme that catalyzes the last reaction in the synthesis of threonine from aspartate. In plants, the methionine pathway shares the same substrate, O-phospho-L-homoserine (OPH), and TS is activated by S-adenosyl-methionine (SAM), a downstream product of methionine synthesis. This positive allosteric effect triggered by the product of another pathway is specific to plants. The crystal structure of Arabidopsis thaliana apo threonine synthase was solved at 2.25 A resolution from triclinic crystals using MAD data from the selenomethionated protein. The structure reveals a four-domain dimer with a two-stranded beta-sheet arm protruding from one monomer onto the other. This domain swap could form a lever through which the allosteric effect is transmitted. The N-terminal domain (domain 1) has a unique fold and is partially disordered, whereas the structural core (domains 2 and 3) shares the functional domain of PLP enzymes of the same family. It also has similarities with SAM-dependent methyltransferases. Structure comparisons allowed us to propose potential sites for pyridoxal-phosphate and SAM binding on TS; they are close to regions that are disordered in the absence of these molecules.
About this Structure
1E5X is a Single protein structure of sequence from Arabidopsis thaliana. Active as Threonine synthase, with EC number 4.2.3.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of threonine synthase from Arabidopsis thaliana., Thomazeau K, Curien G, Dumas R, Biou V, Protein Sci. 2001 Mar;10(3):638-48. PMID:11344332
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