1w2a

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[[Image:1w2a.jpg|left|200px]]
[[Image:1w2a.jpg|left|200px]]
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{{Structure
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|PDB= 1w2a |SIZE=350|CAPTION= <scene name='initialview01'>1w2a</scene>, resolution 2.51&Aring;
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The line below this paragraph, containing "STRUCTURE_1w2a", creates the "Structure Box" on the page.
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|SITE= <scene name='pdbsite=AC1:Fe+Binding+Site+For+Chain+X'>AC1</scene>
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You may change the PDB parameter (which sets the PDB file loaded into the applet)
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|LIGAND= <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=FE:FE+(III)+ION'>FE</scene>
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or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
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|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Deacetoxycephalosporin-C_synthase Deacetoxycephalosporin-C synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.20.1 1.14.20.1] </span>
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or leave the SCENE parameter empty for the default display.
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|GENE=
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|DOMAIN=
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{{STRUCTURE_1w2a| PDB=1w2a | SCENE= }}
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|RELATEDENTRY=
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|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1w2a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1w2a OCA], [http://www.ebi.ac.uk/pdbsum/1w2a PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1w2a RCSB]</span>
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}}
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'''DEACETOXYCEPHALOSPORIN C SYNTHASE (WITH HIS-TAG) COMPLEXED WITH FE(II) AND ETHYLENE GLYCOL'''
'''DEACETOXYCEPHALOSPORIN C SYNTHASE (WITH HIS-TAG) COMPLEXED WITH FE(II) AND ETHYLENE GLYCOL'''
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[[Category: Valegard, K.]]
[[Category: Valegard, K.]]
[[Category: 2-oxoglutarate dependent oxygenase]]
[[Category: 2-oxoglutarate dependent oxygenase]]
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[[Category: cephalosporin]]
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[[Category: Cephalosporin]]
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[[Category: mononuclear ferrous enzyme]]
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[[Category: Mononuclear ferrous enzyme]]
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[[Category: oxidoreductase]]
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[[Category: Oxidoreductase]]
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[[Category: penicillin]]
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[[Category: Penicillin]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 13:03:24 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:30:07 2008''
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Revision as of 10:03, 3 May 2008

Image:1w2a.jpg

Template:STRUCTURE 1w2a

DEACETOXYCEPHALOSPORIN C SYNTHASE (WITH HIS-TAG) COMPLEXED WITH FE(II) AND ETHYLENE GLYCOL


Overview

Deacetoxycephalosporin C synthase (DAOCS) from Streptomyces clavuligerus catalyses the oxidative ring expansion of the penicillin nucleus into the nucleus of cephalosporins. The reaction requires dioxygen and 2-oxoglutarate as co-substrates to create a reactive iron-oxygen intermediate from a ferrous iron in the active site. The active enzyme is monomeric in solution. The structure of DAOCS was determined earlier from merohedrally twinned crystals where the last four C-terminal residues (308-311) of one molecule penetrate the active site of a neighbouring molecule, creating a cyclic trimeric structure in the crystal. Shortening the polypeptide chain from the C terminus by more than four residues diminishes activity. Here, we describe a new crystal form of DAOCS in which trimer formation is broken and the C-terminal arm is free. These crystals show no signs of twinning, and were obtained from DAOCS labelled with an N-terminal His-tag. The modified DAOCS is catalytically active. The free C-terminal arm protrudes into the solvent, and the C-terminal domain (residues 268-299) is rotated by about 16 degrees towards the active site. The last 12 residues (300-311) are disordered. Structures for various enzyme-substrate and enzyme-product complexes in the new crystal form confirm overlapping binding sites for penicillin and 2-oxoglutarate. The results support the notion that 2-oxoglutarate and dioxygen need to react first to produce an oxidizing iron species, followed by reaction with the penicillin substrate. The position of the penicillin nucleus is topologically similar in the two crystal forms, but the penicillin side-chain in the new non-twinned crystals overlaps with the position of residues 304-306 of the C-terminal arm in the twinned crystals. An analysis of the interactions between the C-terminal region and residues in the active site indicates that DAOCS could also accept polypeptide chains as ligands, and these could bind near the iron.

About this Structure

1W2A is a Single protein structure of sequence from Streptomyces clavuligerus. Full crystallographic information is available from OCA.

Reference

Conformational flexibility of the C terminus with implications for substrate binding and catalysis revealed in a new crystal form of deacetoxycephalosporin C synthase., Oster LM, van Scheltinga AC, Valegard K, Hose AM, Dubus A, Hajdu J, Andersson I, J Mol Biol. 2004 Oct 8;343(1):157-71. PMID:15381427 Page seeded by OCA on Sat May 3 13:03:24 2008

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