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New page: left|200px<br /><applet load="1knf" size="450" color="white" frame="true" align="right" spinBox="true" caption="1knf, resolution 1.9Å" /> '''Crystal Structure of ...
 
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[[Image:1knf.gif|left|200px]]<br /><applet load="1knf" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1knf, resolution 1.9&Aring;" />
'''Crystal Structure of 2,3-dihydroxybiphenyl 1,2-dioxygenase Complexed with 3-methyl Catechol under Anaerobic Condition'''<br />


==Overview==
==Crystal Structure of 2,3-dihydroxybiphenyl 1,2-dioxygenase Complexed with 3-methyl Catechol under Anaerobic Condition==
The steady-state cleavage of catechols by 2,3-dihydroxybiphenyl 1, 2-dioxygenase (DHBD), the extradiol dioxygenase of the biphenyl, biodegradation pathway, was investigated using a highly active, anaerobically purified preparation of enzyme. The kinetic data obtained, using 2,3-dihydroxybiphenyl (DHB) fit a compulsory order ternary complex, mechanism in which substrate inhibition occurs. The Km for dioxygen was, 1280 +/- 70 microM, which is at least 2 orders of magnitude higher than, that reported for catechol 2,3-dioxygenases. Km and Kd for DHB were 22 +/-, 2 and 8 +/- 1 microM, respectively. DHBD was subject to reversible, substrate inhibition and mechanism-based inactivation. In air-saturated, buffer, the partition ratios of catecholic substrates substituted at C-3, were inversely related to their apparent specificity constants. Small, organic molecules that stabilized DHBD most effectively also inhibited the, cleavage reaction most strongly. The steady-state kinetic data and, crystallographic results suggest that the stabilization and inhibition are, due to specific interactions between the organic molecule and the active, site of the enzyme. t-Butanol stabilized the enzyme and inhibited the, cleavage of DHB in a mixed fashion, consistent with the distinct binding, sites occupied by t-butanol in the crystal structures of the, substrate-free form of the enzyme and the enzyme-DHB complex. In contrast, crystal structures of complexes with catechol and 3-methylcatechol, revealed relationships between the binding of these smaller substrates and, t-butanol that are consistent with the observed competitive inhibition.
<StructureSection load='1knf' size='340' side='right'caption='[[1knf]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1knf]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Paraburkholderia_xenovorans_LB400 Paraburkholderia xenovorans LB400]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KNF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KNF FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9&#8491;</td></tr>
<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=MBD:3-METHYLCATECHOL'>MBD</scene>, <scene name='pdbligand=TBU:TERTIARY-BUTYL+ALCOHOL'>TBU</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1knf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1knf OCA], [https://pdbe.org/1knf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1knf RCSB], [https://www.ebi.ac.uk/pdbsum/1knf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1knf ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BPHC_PARXL BPHC_PARXL] Shows a preference for catechols with groups immediately adjacent to the hydroxyl substituents.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/kn/1knf_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</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=1knf ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The steady-state cleavage of catechols by 2,3-dihydroxybiphenyl 1, 2-dioxygenase (DHBD), the extradiol dioxygenase of the biphenyl biodegradation pathway, was investigated using a highly active, anaerobically purified preparation of enzyme. The kinetic data obtained using 2,3-dihydroxybiphenyl (DHB) fit a compulsory order ternary complex mechanism in which substrate inhibition occurs. The Km for dioxygen was 1280 +/- 70 microM, which is at least 2 orders of magnitude higher than that reported for catechol 2,3-dioxygenases. Km and Kd for DHB were 22 +/- 2 and 8 +/- 1 microM, respectively. DHBD was subject to reversible substrate inhibition and mechanism-based inactivation. In air-saturated buffer, the partition ratios of catecholic substrates substituted at C-3 were inversely related to their apparent specificity constants. Small organic molecules that stabilized DHBD most effectively also inhibited the cleavage reaction most strongly. The steady-state kinetic data and crystallographic results suggest that the stabilization and inhibition are due to specific interactions between the organic molecule and the active site of the enzyme. t-Butanol stabilized the enzyme and inhibited the cleavage of DHB in a mixed fashion, consistent with the distinct binding sites occupied by t-butanol in the crystal structures of the substrate-free form of the enzyme and the enzyme-DHB complex. In contrast, crystal structures of complexes with catechol and 3-methylcatechol revealed relationships between the binding of these smaller substrates and t-butanol that are consistent with the observed competitive inhibition.


==About this Structure==
Molecular basis for the stabilization and inhibition of 2, 3-dihydroxybiphenyl 1,2-dioxygenase by t-butanol.,Vaillancourt FH, Han S, Fortin PD, Bolin JT, Eltis LD J Biol Chem. 1998 Dec 25;273(52):34887-95. PMID:9857017<ref>PMID:9857017</ref>
1KNF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Burkholderia_cepacia Burkholderia cepacia] with FE2, MBD and TBU as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Biphenyl-2,3-diol_1,2-dioxygenase Biphenyl-2,3-diol 1,2-dioxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.13.11.39 1.13.11.39] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1KNF OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
Molecular basis for the stabilization and inhibition of 2, 3-dihydroxybiphenyl 1,2-dioxygenase by t-butanol., Vaillancourt FH, Han S, Fortin PD, Bolin JT, Eltis LD, J Biol Chem. 1998 Dec 25;273(52):34887-95. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9857017 9857017]
</div>
[[Category: Biphenyl-2,3-diol 1,2-dioxygenase]]
<div class="pdbe-citations 1knf" style="background-color:#fffaf0;"></div>
[[Category: Burkholderia cepacia]]
[[Category: Single protein]]
[[Category: Bolin, J.T.]]
[[Category: Han, S.]]
[[Category: FE2]]
[[Category: MBD]]
[[Category: TBU]]
[[Category: 2]]
[[Category: 3-dihydroxybiphenyl]]
[[Category: 3-methyl catechol]]
[[Category: dioxygenase]]
[[Category: oxidoreductase]]


''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 19:24:48 2007''
==See Also==
*[[Dioxygenase 3D structures|Dioxygenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Paraburkholderia xenovorans LB400]]
[[Category: Bolin JT]]
[[Category: Han S]]