1a5a: Difference between revisions
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<StructureSection load='1a5a' size='340' side='right'caption='[[1a5a]], [[Resolution|resolution]] 1.90Å' scene=''> | <StructureSection load='1a5a' size='340' side='right'caption='[[1a5a]], [[Resolution|resolution]] 1.90Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1a5a]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A5A OCA]. For a <b>guided tour on the structure components</b> use [ | <table><tr><td colspan='2'>[[1a5a]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A5A OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A5A FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene></td></tr> | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene></td></tr> | ||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[ | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Tryptophan_synthase Tryptophan synthase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.20 4.2.1.20] </span></td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[ | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1a5a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a5a OCA], [https://pdbe.org/1a5a PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a5a RCSB], [https://www.ebi.ac.uk/pdbsum/1a5a PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a5a ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Function == | == Function == | ||
[[ | [[https://www.uniprot.org/uniprot/TRPA_SALTY TRPA_SALTY]] The alpha subunit is responsible for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate. [[https://www.uniprot.org/uniprot/TRPB_SALTY TRPB_SALTY]] The beta subunit is responsible for the synthesis of L-tryptophan from indole and L-serine. | ||
== Evolutionary Conservation == | == Evolutionary Conservation == | ||
[[Image:Consurf_key_small.gif|200px|right]] | [[Image:Consurf_key_small.gif|200px|right]] | ||
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==See Also== | ==See Also== | ||
*[[Tryptophan synthase|Tryptophan synthase]] | *[[Tryptophan synthase 3D structures|Tryptophan synthase 3D structures]] | ||
== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 12:42, 26 May 2021
CRYO-CRYSTALLOGRAPHY OF A TRUE SUBSTRATE, INDOLE-3-GLYCEROL PHOSPHATE, BOUND TO A MUTANT (ALPHAD60N) TRYPTOPHAN SYNTHASE ALPHA2BETA2 COMPLEX REVEALS THE CORRECT ORIENTATION OF ACTIVE SITE ALPHA GLU 49CRYO-CRYSTALLOGRAPHY OF A TRUE SUBSTRATE, INDOLE-3-GLYCEROL PHOSPHATE, BOUND TO A MUTANT (ALPHAD60N) TRYPTOPHAN SYNTHASE ALPHA2BETA2 COMPLEX REVEALS THE CORRECT ORIENTATION OF ACTIVE SITE ALPHA GLU 49
Structural highlights
Function[TRPA_SALTY] The alpha subunit is responsible for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate. [TRPB_SALTY] The beta subunit is responsible for the synthesis of L-tryptophan from indole and L-serine. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe reversible cleavage of indole-3-glycerol by the alpha-subunit of tryptophan synthase has been proposed to be catalyzed by alphaGlu49 and alphaAsp60. Although previous x-ray crystallographic structures of the tryptophan synthase alpha2beta2 complex showed an interaction between the carboxylate of alphaAsp60 and the bound inhibitor indole-3-propanol phosphate, the carboxylate of alphaGlu49 was too distant to play its proposed role. To clarify the structural and functional roles of alphaGlu49, we have determined crystal structures of a mutant (alphaD60N) alpha2beta2 complex in the presence and absence of the true substrate, indole-3-glycerol phosphate. The enzyme in the crystal cleaves indole-3-glycerol phosphate very slowly at room temperature but not under cryo-conditions of 95 K. The structure of the complex with the true substrate obtained by cryo-crystallography reveals that indole-3-glycerol phosphate and indole-3-propanol phosphate have similar binding modes but different torsion angles. Most importantly, the side chain of alphaGlu49 interacts with 3-hydroxyl group of indole-3-glycerol phosphate as proposed. The movement of the side chain of alphaGlu49 into an extended conformation upon binding the true substrate provides evidence for an induced fit mechanism. Our results demonstrate how cryo-crystallography and mutagenesis can provide insight into enzyme mechanism. Cryo-crystallography of a true substrate, indole-3-glycerol phosphate, bound to a mutant (alphaD60N) tryptophan synthase alpha2beta2 complex reveals the correct orientation of active site alphaGlu49.,Rhee S, Miles EW, Davies DR J Biol Chem. 1998 Apr 10;273(15):8553-5. PMID:9535826[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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