1hb1

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[[Image:1hb1.gif|left|200px]]<br />
 
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<applet load="1hb1" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1hb1, resolution 1.55&Aring;" />
 
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'''ISOPENICILLIN N SYNTHASE FROM ASPERGILLUS NIDULANS (ANAEROBIC ACOV FE COMPLEX)'''<br />
 
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==Overview==
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==ISOPENICILLIN N SYNTHASE FROM ASPERGILLUS NIDULANS (ANAEROBIC ACOV FE COMPLEX)==
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BACKGROUND: Isopenicillin N synthase (IPNS) catalyses formation of, bicyclic isopenicillin N, precursor to all penicillin and cephalosporin, antibiotics, from the linear tripeptide, delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine. IPNS is a non-haem, iron(II)-dependent enzyme which utilises the full oxidising potential of, molecular oxygen in catalysing the bicyclisation reaction. The reaction, mechanism is believed to involve initial formation of the beta-lactam ring, (via a thioaldehyde intermediate) to give an iron(IV)-oxo species, which, then mediates closure of the 5-membered thiazolidine ring. RESULTS: Here, we report experiments employing time-resolved crystallography to observe, turnover of an isosteric substrate analogue designed to intercept the, catalytic pathway at an early stage. Reaction in the crystalline, enzyme-substrate complex was initiated by the application of high-pressure, oxygen, and subsequent flash freezing allowed an oxygenated product to be, trapped, bound at the iron centre. A mechanism for formation of the, observed thiocarboxylate product is proposed. CONCLUSIONS: In the absence, of its natural reaction partner (the N-H proton of the, L-cysteinyl-D-valine amide bond), the proposed hydroperoxide intermediate, appears to attack the putative thioaldehyde species directly. These, results shed light on the events preceding beta-lactam closure in the IPNS, reaction cycle, and enhance our understanding of the mechanism for, reaction of the enzyme with its natural substrate.
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<StructureSection load='1hb1' size='340' side='right'caption='[[1hb1]], [[Resolution|resolution]] 1.55&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[1hb1]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Aspergillus_nidulans Aspergillus nidulans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HB1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1HB1 FirstGlance]. <br>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.55&#8491;</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE2:FE+(II)+ION'>FE2</scene>, <scene name='pdbligand=OCV:N6-[(1R)-2-{[(1R)-1-CARBOXY-2-METHYLPROPYL]OXY}-1-(MERCAPTOMETHYL)-2-OXOETHYL]-6-OXO-D-LYSINE'>OCV</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1hb1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hb1 OCA], [https://pdbe.org/1hb1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1hb1 RCSB], [https://www.ebi.ac.uk/pdbsum/1hb1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1hb1 ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/IPNA_EMENI IPNA_EMENI] Isopenicillin N synthase; part of the gene cluster that mediates the biosynthesis of penicillin, the world's most important antibiotic (PubMed:3319778, PubMed:11755401). IpnA catalyzes the cyclization of the tripeptide N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine (LLD-ACV or ACV) to form isopenicillin N (IPN) that contains the beta-lactam nucleus (PubMed:3319778, PubMed:11755401, PubMed:28703303). The penicillin biosynthesis occurs via 3 enzymatic steps, the first corresponding to the production of the tripeptide N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine (LLD-ACV or ACV) by the NRPS acvA. The tripeptide ACV is then cyclized to isopenicillin N (IPN) by the isopenicillin N synthase ipnA that forms the beta-lactam nucleus. Finally, the alpha-aminoadipyl side chain is exchanged for phenylacetic acid by the isopenicillin N acyltransferase penDE to yield penicillin in the peroxisomal matrix (By similarity).[UniProtKB:P08703]<ref>PMID:11755401</ref> <ref>PMID:28703303</ref> <ref>PMID:3319778</ref>
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/hb/1hb1_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1hb1 ConSurf].
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<div style="clear:both"></div>
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<div style="background-color:#fffaf0;">
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== Publication Abstract from PubMed ==
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BACKGROUND: Isopenicillin N synthase (IPNS) catalyses formation of bicyclic isopenicillin N, precursor to all penicillin and cephalosporin antibiotics, from the linear tripeptide delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine. IPNS is a non-haem iron(II)-dependent enzyme which utilises the full oxidising potential of molecular oxygen in catalysing the bicyclisation reaction. The reaction mechanism is believed to involve initial formation of the beta-lactam ring (via a thioaldehyde intermediate) to give an iron(IV)-oxo species, which then mediates closure of the 5-membered thiazolidine ring. RESULTS: Here we report experiments employing time-resolved crystallography to observe turnover of an isosteric substrate analogue designed to intercept the catalytic pathway at an early stage. Reaction in the crystalline enzyme-substrate complex was initiated by the application of high-pressure oxygen, and subsequent flash freezing allowed an oxygenated product to be trapped, bound at the iron centre. A mechanism for formation of the observed thiocarboxylate product is proposed. CONCLUSIONS: In the absence of its natural reaction partner (the N-H proton of the L-cysteinyl-D-valine amide bond), the proposed hydroperoxide intermediate appears to attack the putative thioaldehyde species directly. These results shed light on the events preceding beta-lactam closure in the IPNS reaction cycle, and enhance our understanding of the mechanism for reaction of the enzyme with its natural substrate.
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==About this Structure==
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Alternative oxidation by isopenicillin N synthase observed by X-ray diffraction.,Ogle JM, Clifton IJ, Rutledge PJ, Elkins JM, Burzlaff NI, Adlington RM, Roach PL, Baldwin JE Chem Biol. 2001 Dec;8(12):1231-7. PMID:11755401<ref>PMID:11755401</ref>
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1HB1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Emericella_nidulans Emericella nidulans] with SO4, FE2 and OCV as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: OCV. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1HB1 OCA].
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==Reference==
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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Alternative oxidation by isopenicillin N synthase observed by X-ray diffraction., Ogle JM, Clifton IJ, Rutledge PJ, Elkins JM, Burzlaff NI, Adlington RM, Roach PL, Baldwin JE, Chem Biol. 2001 Dec;8(12):1231-7. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11755401 11755401]
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</div>
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[[Category: Emericella nidulans]]
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<div class="pdbe-citations 1hb1" style="background-color:#fffaf0;"></div>
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[[Category: Single protein]]
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[[Category: Adlington, R.M.]]
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[[Category: Baldwin, J.E.]]
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[[Category: Burzlaff, N.I.]]
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[[Category: Clifton, I.J.]]
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[[Category: Elkins, J.M.]]
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[[Category: Ogle, J.M.]]
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[[Category: Roach, P.L.]]
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[[Category: Rutledge, P.J.]]
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[[Category: FE2]]
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[[Category: OCV]]
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[[Category: SO4]]
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[[Category: antibiotic biosynthesis]]
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[[Category: b-lactam antibiotic]]
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[[Category: oxygenase]]
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[[Category: penicillin biosynthesis]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:45:55 2007''
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==See Also==
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*[[Isopenicillin N synthase|Isopenicillin N synthase]]
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== References ==
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<references/>
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__TOC__
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</StructureSection>
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[[Category: Aspergillus nidulans]]
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[[Category: Large Structures]]
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[[Category: Adlington RM]]
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[[Category: Baldwin JE]]
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[[Category: Burzlaff NI]]
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[[Category: Clifton IJ]]
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[[Category: Elkins JM]]
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[[Category: Ogle JM]]
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[[Category: Roach PL]]
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[[Category: Rutledge PJ]]

Current revision

ISOPENICILLIN N SYNTHASE FROM ASPERGILLUS NIDULANS (ANAEROBIC ACOV FE COMPLEX)

PDB ID 1hb1

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