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| | {{STRUCTURE_2tsy| PDB=2tsy | SCENE= }} | | {{STRUCTURE_2tsy| PDB=2tsy | SCENE= }} |
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| - | '''CRYSTAL STRUCTURES OF MUTANT (BETAK87T) TRYPTOPHAN SYNTHASE ALPHA2 BETA2 COMPLEX WITH LIGANDS BOUND TO THE ACTIVE SITES OF THE ALPHA AND BETA SUBUNITS REVEAL LIGAND-INDUCED CONFORMATIONAL CHANGES'''
| + | ===CRYSTAL STRUCTURES OF MUTANT (BETAK87T) TRYPTOPHAN SYNTHASE ALPHA2 BETA2 COMPLEX WITH LIGANDS BOUND TO THE ACTIVE SITES OF THE ALPHA AND BETA SUBUNITS REVEAL LIGAND-INDUCED CONFORMATIONAL CHANGES=== |
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| - | ==Overview==
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| - | Three-dimensional structures are reported for a mutant (betaK87T) tryptophan synthase alpha2beta2 complex with either the substrate L-serine (betaK87T-Ser) or product L-tryptophan (betaK87T-Trp) at the active site of the beta-subunit, in which both amino acids form external aldimines with the coenzyme, pyridoxal phosphate. We also present structures with L-serine bound to the beta site and either alpha-glycerol 3-phosphate (betaK87T-Ser-GP) or indole-3-propanol phosphate (betaK87T-Ser-IPP) bound to the active site of the alpha-subunit. The results further identify the substrate and product binding sites in each subunit and provide insight into conformational changes that occur upon formation of these complexes. The two structures having ligands at the active sites of both alpha- and beta-subunits reveal an important new feature, the ordering of alpha-subunit loop 6 (residues 179-187). Closure of loop 6 isolates the active site of the alpha-subunit from solvent and results in interaction between alphaThr183 and the catalytic residue alphaAsp60. Other conformational differences between the wild type and these two mutant structures include a rigid-body rotation of the alpha-subunit of approximately 5 degrees relative to the beta-subunit and large movements of part of the beta-subunit (residues 93-189) toward the rest of the beta-subunit. Much smaller differences are observed in the betaK87T-Ser structure. Remarkably, binding of tryptophan to the beta active site results in conformational changes very similar to those observed in the betaK87T-Ser-GP and betaK87T-Ser-IPP structures, with exception of the disordered alpha-subunit loop 6. These large-scale changes, the closure of loop 6, and the movements of a small number of side chains in the alpha-beta interaction site provide a structural base for interpreting the allosteric properties of tryptophan synthase.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9201907}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 9201907 is the PubMed ID number. |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Pyridoxal phosphate]] | | [[Category: Pyridoxal phosphate]] |
| | [[Category: Tryptophan biosynthesis]] | | [[Category: Tryptophan biosynthesis]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 17:27:27 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 12:30:47 2008'' |
Revision as of 09:30, 29 July 2008
Template:STRUCTURE 2tsy
CRYSTAL STRUCTURES OF MUTANT (BETAK87T) TRYPTOPHAN SYNTHASE ALPHA2 BETA2 COMPLEX WITH LIGANDS BOUND TO THE ACTIVE SITES OF THE ALPHA AND BETA SUBUNITS REVEAL LIGAND-INDUCED CONFORMATIONAL CHANGES
Template:ABSTRACT PUBMED 9201907
About this Structure
2TSY is a Protein complex structure of sequences from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
Crystal structures of a mutant (betaK87T) tryptophan synthase alpha2beta2 complex with ligands bound to the active sites of the alpha- and beta-subunits reveal ligand-induced conformational changes., Rhee S, Parris KD, Hyde CC, Ahmed SA, Miles EW, Davies DR, Biochemistry. 1997 Jun 24;36(25):7664-80. PMID:9201907
Page seeded by OCA on Tue Jul 29 12:30:47 2008
