View source for 3ojn


==Structure of Mn-substituted Homoprotocatechuate 2,3-Dioxygenase at 1.65 Ang resolution==
<StructureSection load='3ojn' size='340' side='right'caption='[[3ojn]], [[Resolution|resolution]] 1.65&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ojn]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Brevibacterium_fuscum Brevibacterium fuscum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3OJN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3OJN 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]] 1.65&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=P6G:HEXAETHYLENE+GLYCOL'>P6G</scene>, <scene name='pdbligand=PG4:TETRAETHYLENE+GLYCOL'>PG4</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=3ojn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ojn OCA], [https://pdbe.org/3ojn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ojn RCSB], [https://www.ebi.ac.uk/pdbsum/3ojn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ojn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q45135_9MICO Q45135_9MICO] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD) has an Fe(II) center in its active site that can be replaced with Mn(II) or Co(II). Whereas Mn-HPCD exhibits steady-state kinetic parameters comparable to those of Fe-HPCD, Co-HPCD behaves somewhat differently, exhibiting significantly higher [Formula: see text] and k (cat). The high activity of Co-HPCD is surprising, given that cobalt has the highest standard M(III/II) redox potential of the three metals. Comparison of the X-ray crystal structures of the resting and substrate-bound forms of Fe-HPCD, Mn-HPCD, and Co-HPCD shows that metal substitution has no effect on the local ligand environment, the conformational integrity of the active site, or the overall protein structure, suggesting that the protein structure does not differentially tune the potential of the metal center. Analysis of the steady-state kinetics of Co-HPCD suggests that the Co(II) center alters the relative rate constants for the interconversion of intermediates in the catalytic cycle but still allows the dioxygenase reaction to proceed efficiently. When compared with the kinetic data for Fe-HPCD and Mn-HPCD, these results show that dioxygenase catalysis can proceed at high rates over a wide range of metal redox potentials. This is consistent with the proposed mechanism in which the metal mediates electron transfer between the catechol substrate and O(2) to form the postulated [M(II)(semiquinone)superoxo] reactive species. These kinetic differences and the spectroscopic properties of Co-HPCD provide new tools with which to explore the unique O(2) activation mechanism associated with the extradiol dioxygenase family.

A hyperactive cobalt-substituted extradiol-cleaving catechol dioxygenase.,Fielding AJ, Kovaleva EG, Farquhar ER, Lipscomb JD, Que L Jr J Biol Inorg Chem. 2010 Dec 14. PMID:21153851<ref>PMID:21153851</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3ojn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Dioxygenase|Dioxygenase]]
*[[Dioxygenase 3D structures|Dioxygenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Brevibacterium fuscum]]
[[Category: Large Structures]]
[[Category: Farquhar ER]]
[[Category: Fielding AJ]]
[[Category: Kovaleva EG]]
[[Category: Lipscomb JD]]
[[Category: Que Jr L]]