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1qr7

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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'''
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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===
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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.
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{{ABSTRACT_PUBMED_10425687}}
==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]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:36:45 2008''
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''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

Image:1qr7.png

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

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