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[[Image:1uxr.gif|left|200px]]
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{{STRUCTURE_1uxr|  PDB=1uxr  |  SCENE=  }}
'''STRUCTURAL BASIS FOR ALLOSTERIC REGULATION AND SUBSTRATE SPECIFICITY OF THE NON-PHOSPHORYLATING GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPN) FROM THERMOPROTEUS TENAX'''


==Structural basis for allosteric regulation and substrate specificity of the non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) from Thermoproteus tenax==
<StructureSection load='1uxr' size='340' side='right'caption='[[1uxr]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1uxr]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermoproteus_tenax Thermoproteus tenax]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UXR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1UXR FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=F6P:FRUCTOSE-6-PHOSPHATE'>F6P</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=NAP:NADP+NICOTINAMIDE-ADENINE-DINUCLEOTIDE+PHOSPHATE'>NAP</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1uxr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1uxr OCA], [https://pdbe.org/1uxr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1uxr RCSB], [https://www.ebi.ac.uk/pdbsum/1uxr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1uxr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GAPN_THETE GAPN_THETE] Catalyzes the irreversible NAD(P)-dependent non-phosphorylating oxidation of glyceraldehyde-3-phosphate (GAP) to 3-phosphoglycerate (3PG). It is highly specific for D-GAP.<ref>PMID:3121324</ref> <ref>PMID:9497334</ref>
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ux/1uxr_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1uxr ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) of the hyperthermophilic Archaeum Thermoproteus tenax is a member of the superfamily of aldehyde dehydrogenases (ALDH). GAPN catalyses the irreversible oxidation of glyceraldehyde 3-phosphate (GAP) to 3-phosphoglycerate in the modified glycolytic pathway of this organism. In contrast to other members of the ALDH superfamily, GAPN from T.tenax (Tt-GAPN) is regulated by a number of intermediates and metabolites. In the NAD-dependent oxidation of GAP, glucose 1-phosphate, fructose 6-phosphate, AMP and ADP increase the affinity for the cosubstrate, whereas ATP, NADP, NADPH and NADH decrease it leaving, however, the catalytic rate virtually unaltered. As we show here, the enzyme also uses NADP as a cosubstrate, displaying, however, unusual discontinuous saturation kinetics indicating different cosubstrate affinities and/or reactivities of the four active sites of the protein tetramer caused by cooperative effects. Furthermore, in the NADP-dependent reaction the presence of activators decreases the overall S0.5 and increases Vmax by a factor of 3. To explore the structural basis for the different effects of both pyridine nucleotides we solved the crystal structure of Tt-GAPN in complex with NAD at 2.2 A resolution and compared it to the binary Tt-GAPN-NADPH structure. Although both pyridine nucleotides show a similar binding mode, NADPH appears to be more tightly bound to the protein via the 2' phosphate moiety. Moreover, we present four co-crystal structures with the activating molecules glucose 1-phosphate, fructose 6-phosphate, AMP and ADP determined at resolutions ranging from 2.3 A to 2.6 A. These crystal structures reveal a common regulatory site able to accommodate the different activators. A phosphate-binding pocket serves as an anchor point ensuring similar binding geometry. The observed conformational changes upon activator binding are discussed in terms of allosteric regulation. Furthermore, we present a crystal structure of Tt-GAPN in complex with the substrate D-GAP at 2.3 A resolution, which allows us to analyse the structural basis for substrate binding, the mechanism of catalysis as well as the stereoselectivity of the enzymatic reaction.


==Overview==
Structural Basis of allosteric regulation and substrate specificity of the non-phosphorylating glyceraldehyde 3-Phosphate dehydrogenase from Thermoproteus tenax.,Lorentzen E, Hensel R, Knura T, Ahmed H, Pohl E J Mol Biol. 2004 Aug 13;341(3):815-28. PMID:15288789<ref>PMID:15288789</ref>
The non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) of the hyperthermophilic Archaeum Thermoproteus tenax is a member of the superfamily of aldehyde dehydrogenases (ALDH). GAPN catalyses the irreversible oxidation of glyceraldehyde 3-phosphate (GAP) to 3-phosphoglycerate in the modified glycolytic pathway of this organism. In contrast to other members of the ALDH superfamily, GAPN from T.tenax (Tt-GAPN) is regulated by a number of intermediates and metabolites. In the NAD-dependent oxidation of GAP, glucose 1-phosphate, fructose 6-phosphate, AMP and ADP increase the affinity for the cosubstrate, whereas ATP, NADP, NADPH and NADH decrease it leaving, however, the catalytic rate virtually unaltered. As we show here, the enzyme also uses NADP as a cosubstrate, displaying, however, unusual discontinuous saturation kinetics indicating different cosubstrate affinities and/or reactivities of the four active sites of the protein tetramer caused by cooperative effects. Furthermore, in the NADP-dependent reaction the presence of activators decreases the overall S0.5 and increases Vmax by a factor of 3. To explore the structural basis for the different effects of both pyridine nucleotides we solved the crystal structure of Tt-GAPN in complex with NAD at 2.2 A resolution and compared it to the binary Tt-GAPN-NADPH structure. Although both pyridine nucleotides show a similar binding mode, NADPH appears to be more tightly bound to the protein via the 2' phosphate moiety. Moreover, we present four co-crystal structures with the activating molecules glucose 1-phosphate, fructose 6-phosphate, AMP and ADP determined at resolutions ranging from 2.3 A to 2.6 A. These crystal structures reveal a common regulatory site able to accommodate the different activators. A phosphate-binding pocket serves as an anchor point ensuring similar binding geometry. The observed conformational changes upon activator binding are discussed in terms of allosteric regulation. Furthermore, we present a crystal structure of Tt-GAPN in complex with the substrate D-GAP at 2.3 A resolution, which allows us to analyse the structural basis for substrate binding, the mechanism of catalysis as well as the stereoselectivity of the enzymatic reaction.


==About this Structure==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
1UXR is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Thermoproteus_tenax Thermoproteus tenax]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UXR OCA].
</div>
<div class="pdbe-citations 1uxr" style="background-color:#fffaf0;"></div>


==Reference==
==See Also==
Structural Basis of allosteric regulation and substrate specificity of the non-phosphorylating glyceraldehyde 3-Phosphate dehydrogenase from Thermoproteus tenax., Lorentzen E, Hensel R, Knura T, Ahmed H, Pohl E, J Mol Biol. 2004 Aug 13;341(3):815-28. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15288789 15288789]
*[[Aldehyde dehydrogenase 3D structures|Aldehyde dehydrogenase 3D structures]]
[[Category: Single protein]]
*[[Glyceraldehyde-3-phosphate dehydrogenase 3D structures|Glyceraldehyde-3-phosphate dehydrogenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermoproteus tenax]]
[[Category: Thermoproteus tenax]]
[[Category: Hensel, R.]]
[[Category: Hensel R]]
[[Category: Lorentzen, E.]]
[[Category: Lorentzen E]]
[[Category: Pohl, E.]]
[[Category: Pohl E]]
[[Category: Aldh]]
[[Category: Catalysis]]
[[Category: Fructose 6-phosphate]]
[[Category: Gapn]]
[[Category: Glycolysis]]
[[Category: Oxidoreductase]]
[[Category: Regulation]]
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