1tb4
From Proteopedia
(New page: 200px<br /><applet load="1tb4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tb4, resolution 2.15Å" /> '''Crystal Structure of...) |
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| - | [[Image:1tb4.gif|left|200px]]<br /><applet load="1tb4" size=" | + | [[Image:1tb4.gif|left|200px]]<br /><applet load="1tb4" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1tb4, resolution 2.15Å" /> | caption="1tb4, resolution 2.15Å" /> | ||
'''Crystal Structure of Aspartate-Semialdehyde Dehydrogenase From Haemophilus influenzae with a Bound Periodate'''<br /> | '''Crystal Structure of Aspartate-Semialdehyde Dehydrogenase From Haemophilus influenzae with a Bound Periodate'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The reversible dephosphorylation of beta-aspartyl phosphate to | + | The reversible dephosphorylation of beta-aspartyl phosphate to L-aspartate-beta-semialdehyde (ASA) in the aspartate biosynthetic pathway is catalyzed by aspartate-beta-semialdehyde dehydrogenase (ASADH). The phosphate that is present to activate the aspartate carboxyl group is held in a separate and distinct binding site once removed and prior to its release from the enzyme. This site had been shown to be selective for tetrahedral oxyanions, with several competitive inhibitors and alternative substrates previously identified for the reverse reaction. Structural studies have now shown that the most potent oxyanion inhibitor (periodate) and a good alternative substrate (arsenate) each occupy the same catalytic phosphate-binding site. However, a rotation of a threonine side chain (Thr137) in the periodate complex disrupts an important hydrogen-bonding interaction with an active-site glutamate (Glu243) that participates in substrate orientation. This subtle change appears to be the difference between a substrate and an inhibitor of this enzyme. |
==About this Structure== | ==About this Structure== | ||
| - | 1TB4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Haemophilus_influenzae Haemophilus influenzae] with PEJ as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Aspartate-semialdehyde_dehydrogenase Aspartate-semialdehyde dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.2.1.11 1.2.1.11] Full crystallographic information is available from [http:// | + | 1TB4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Haemophilus_influenzae Haemophilus influenzae] with <scene name='pdbligand=PEJ:'>PEJ</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Aspartate-semialdehyde_dehydrogenase Aspartate-semialdehyde dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.2.1.11 1.2.1.11] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TB4 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Haemophilus influenzae]] | [[Category: Haemophilus influenzae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Viola, R | + | [[Category: Viola, R E.]] |
[[Category: PEJ]] | [[Category: PEJ]] | ||
[[Category: aspartate biosynthetic pathway]] | [[Category: aspartate biosynthetic pathway]] | ||
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[[Category: periodate]] | [[Category: periodate]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:11:47 2008'' |
Revision as of 13:11, 21 February 2008
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Crystal Structure of Aspartate-Semialdehyde Dehydrogenase From Haemophilus influenzae with a Bound Periodate
Overview
The reversible dephosphorylation of beta-aspartyl phosphate to L-aspartate-beta-semialdehyde (ASA) in the aspartate biosynthetic pathway is catalyzed by aspartate-beta-semialdehyde dehydrogenase (ASADH). The phosphate that is present to activate the aspartate carboxyl group is held in a separate and distinct binding site once removed and prior to its release from the enzyme. This site had been shown to be selective for tetrahedral oxyanions, with several competitive inhibitors and alternative substrates previously identified for the reverse reaction. Structural studies have now shown that the most potent oxyanion inhibitor (periodate) and a good alternative substrate (arsenate) each occupy the same catalytic phosphate-binding site. However, a rotation of a threonine side chain (Thr137) in the periodate complex disrupts an important hydrogen-bonding interaction with an active-site glutamate (Glu243) that participates in substrate orientation. This subtle change appears to be the difference between a substrate and an inhibitor of this enzyme.
About this Structure
1TB4 is a Single protein structure of sequence from Haemophilus influenzae with as ligand. Active as Aspartate-semialdehyde dehydrogenase, with EC number 1.2.1.11 Full crystallographic information is available from OCA.
Reference
Structural basis for discrimination between oxyanion substrates or inhibitors in aspartate-beta-semialdehyde dehydrogenase., Faehnle CR, Blanco J, Viola RE, Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 2):2320-4. Epub, 2004 Nov 26. PMID:15583380
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