1a5a: Difference between revisions
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'''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 49''' | {{Structure | ||
|PDB= 1a5a |SIZE=350|CAPTION= <scene name='initialview01'>1a5a</scene>, resolution 1.9Å | |||
|SITE= <scene name='pdbsite=PLP:Coenzyme+Plp+Binding+Site'>PLP</scene> | |||
|LIGAND= <scene name='pdbligand=K:POTASSIUM+ION'>K</scene> and <scene name='pdbligand=PLP:PYRIDOXAL-5'-PHOSPHATE'>PLP</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Tryptophan_synthase Tryptophan synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.20 4.2.1.20] | |||
|GENE= TRPA/TRPB ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=602 Salmonella typhimurium]) | |||
}} | |||
'''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 49''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1A5A is a [ | 1A5A is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A5A OCA]. | ||
==Reference== | ==Reference== | ||
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:[http:// | 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:[http://www.ncbi.nlm.nih.gov/pubmed/9535826 9535826] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Salmonella typhimurium]] | [[Category: Salmonella typhimurium]] | ||
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[[Category: mutation at position 60 (asp --> asn) in the a-subunit]] | [[Category: mutation at position 60 (asp --> asn) in the a-subunit]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 09:53:07 2008'' | ||
Revision as of 10:53, 20 March 2008
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| , resolution 1.9Å | |||||||
|---|---|---|---|---|---|---|---|
| Sites: | |||||||
| Ligands: | and | ||||||
| Gene: | TRPA/TRPB (Salmonella typhimurium) | ||||||
| Activity: | Tryptophan synthase, with EC number 4.2.1.20 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
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 49
OverviewOverview
The 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.
About this StructureAbout this Structure
1A5A is a Protein complex structure of sequences from Salmonella typhimurium. Full crystallographic information is available from OCA.
ReferenceReference
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 [[Category: mutation at position 60 (asp --> asn) in the a-subunit]]
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