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| | {{STRUCTURE_1qr7| PDB=1qr7 | SCENE= }} | | {{STRUCTURE_1qr7| PDB=1qr7 | SCENE= }} |
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| - | '''CRYSTAL STRUCTURE OF PHENYLALANINE-REGULATED 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE SYNTHASE FROM ESCHERICHIA COLI COMPLEXED WITH PB2+ AND PEP'''
| + | ===CRYSTAL STRUCTURE OF PHENYLALANINE-REGULATED 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE SYNTHASE FROM ESCHERICHIA COLI COMPLEXED WITH PB2+ AND PEP=== |
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| - | ==Overview==
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| - | BACKGROUND: In microorganisms and plants the first step in the common pathway leading to the biosynthesis of aromatic compounds is the stereospecific condensation of phosphoenolpyruvate (PEP) and D-erythrose-4-phosphate (E4P) giving rise to 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP). This reaction is catalyzed by DAHP synthase (DAHPS), a metal-activated enzyme, which in microorganisms is the target for negative-feedback regulation by pathway intermediates or by end products. In Escherichia coli there are three DAHPS isoforms, each specifically inhibited by one of the three aromatic amino acids. RESULTS: The crystal structure of the phenylalanine-regulated form of DAHPS complexed with PEP and Pb2+ (DAHPS(Phe)-PEP-Pb) was determined by multiple wavelength anomalous dispersion phasing utilizing the anomalous scattering of Pb2+. The tetramer consists of two tight dimers. The monomers of the tight dimer are coupled by extensive interactions including a pair of three-stranded, intersubunit beta sheets. The monomer (350 residues) is a (beta/alpha)8 barrel with several additional beta strands and alpha helices. The PEP and Pb2+ are at the C-ends of the beta strands of the barrel, as is SO4(2-), inferred to occupy the position of the phosphate of E4P. Mutations that reduce feedback inhibition cluster about a cavity near the twofold axis of the tight dimer and are centered approximately 15 A from the active site, indicating the location of a separate regulatory site. CONCLUSIONS: The crystal structure of DAHPS(Phe)-PEP-Pb reveals the active site of this key enzyme of aromatic biosynthesis and indicates the probable site of inhibitor binding. This is the first reported structure of a DAHPS; the structure of its two paralogs and of a variety of orthologs should now be readily determined by molecular replacement.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_10425687}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 10425687 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_10425687}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Shumilin, I A.]] | | [[Category: Shumilin, I A.]] |
| | [[Category: Beta-alpha-barrel]] | | [[Category: Beta-alpha-barrel]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:36:45 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 08:33:38 2008'' |
Revision as of 05:33, 28 July 2008
Template:STRUCTURE 1qr7
CRYSTAL STRUCTURE OF PHENYLALANINE-REGULATED 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE SYNTHASE FROM ESCHERICHIA COLI COMPLEXED WITH PB2+ AND PEP
Template:ABSTRACT PUBMED 10425687
About this Structure
1QR7 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of phenylalanine-regulated 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase from Escherichia coli., Shumilin IA, Kretsinger RH, Bauerle RH, Structure. 1999 Jul 15;7(7):865-75. PMID:10425687
Page seeded by OCA on Mon Jul 28 08:33:38 2008
