View source for 1koq


==NEISSERIA GONORRHOEAE CARBONIC ANHYDRASE==
<StructureSection load='1koq' size='340' side='right'caption='[[1koq]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1koq]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Neisseria_gonorrhoeae Neisseria gonorrhoeae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KOQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KOQ 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=ZN:ZINC+ION'>ZN</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=1koq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1koq OCA], [https://pdbe.org/1koq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1koq RCSB], [https://www.ebi.ac.uk/pdbsum/1koq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1koq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAH_NEIGO CAH_NEIGO] Reversible hydration of carbon dioxide.
== 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/ko/1koq_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1koq ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure of carbonic anhydrase from Neisseria gonorrhoeae has been solved to a resolution of 1.78 A by molecular replacement using human carbonic anhydrase II as a template. After refinement the R factor was 17.8% (Rfree=23.2%). There are two molecules per asymmetric unit (space group P21), but they have essentially identical structures. The fold of the N. gonorrhoeae enzyme is very similar to that of human isozyme II; 192 residues, 74 of which are identical in the two enzymes, have equivalent positions in the three-dimensional structures. This corresponds to 85% of the entire polypeptide chain of the bacterial enzyme. The only two cysteine residues in the bacterial enzyme, which has a periplasmic location in the cell, are connected by a disulfide bond. Most of the secondary structure elements present in human isozyme II are retained in N. gonorrhoeae carbonic anhydrase, but there are also differences, particularly in the few helical regions. Long deletions in the bacterial enzyme relative to human isozyme II have resulted in a considerable shortening of three surface loops. One of these deletions, corresponding to residues 128 to 139 in the human enzyme, leads to a widening of the entrance to the hydrophobic part of the active site cavity. Practically all the amino acid residues in the active site of human isozyme II are conserved in the N. gonorrhoeae enzyme and have similar structural positions. However, the imidazole ring of a histidine residue, which has been shown to function as a proton shuttle in the catalytic mechanism of the human enzyme, interacts with an extraneous entity, which has tentatively been identified as a 2-mercaptoethanol molecule from the crystallization medium. When this entity is removed by soaking the crystal in a different medium, the side-chain of His66 becomes quite mobile. The structure of a complex with the sulfonamide inhibitor, acetazolamide, has also been determined. Its position in the active site is very similar to that observed in human carbonic anhydrase II.

Crystal structure of carbonic anhydrase from Neisseria gonorrhoeae and its complex with the inhibitor acetazolamide.,Huang S, Xue Y, Sauer-Eriksson E, Chirica L, Lindskog S, Jonsson BH J Mol Biol. 1998;283(1):301-10. PMID:9761692<ref>PMID:9761692</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1koq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Carbonic anhydrase 3D structures|Carbonic anhydrase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Neisseria gonorrhoeae]]
[[Category: Chirica L]]
[[Category: Huang S]]
[[Category: Jonsson B-H]]
[[Category: Lindskog S]]
[[Category: Xue Y]]