View source for 3ks3

==High resolution structure of Human Carbonic Anhydrase II at 0.9 A==
<StructureSection load='3ks3' size='340' side='right' caption='[[3ks3]], [[Resolution|resolution]] 0.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ks3]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3KS3 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3KS3 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CA2 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Carbonate_dehydratase Carbonate dehydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.1 4.2.1.1] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ks3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ks3 OCA], [http://pdbe.org/3ks3 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3ks3 RCSB], [http://www.ebi.ac.uk/pdbsum/3ks3 PDBsum]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/CAH2_HUMAN CAH2_HUMAN]] Defects in CA2 are the cause of osteopetrosis autosomal recessive type 3 (OPTB3) [MIM:[http://omim.org/entry/259730 259730]]; also known as osteopetrosis with renal tubular acidosis, carbonic anhydrase II deficiency syndrome, Guibaud-Vainsel syndrome or marble brain disease. Osteopetrosis is a rare genetic disease characterized by abnormally dense bone, due to defective resorption of immature bone. The disorder occurs in two forms: a severe autosomal recessive form occurring in utero, infancy, or childhood, and a benign autosomal dominant form occurring in adolescence or adulthood. Autosomal recessive osteopetrosis is usually associated with normal or elevated amount of non-functional osteoclasts. OPTB3 is associated with renal tubular acidosis, cerebral calcification (marble brain disease) and in some cases with mental retardation.<ref>PMID:1928091</ref> <ref>PMID:1542674</ref> <ref>PMID:8834238</ref> <ref>PMID:9143915</ref> <ref>PMID:15300855</ref>  
== Function ==
[[http://www.uniprot.org/uniprot/CAH2_HUMAN CAH2_HUMAN]] Essential for bone resorption and osteoclast differentiation (By similarity). Reversible hydration of carbon dioxide. Can hydrate cyanamide to urea. Involved in the regulation of fluid secretion into the anterior chamber of the eye.<ref>PMID:10550681</ref> <ref>PMID:11831900</ref>  
== 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/ks/3ks3_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=3ks3 ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure of human carbonic anhydrase II (HCA II) obtained at 0.9 A resolution reveals that a water molecule, termed deep water, Dw, and bound in a hydrophobic pocket of the active site forms a short, strong hydrogen bond with the zinc-bound solvent molecule, a conclusion based on the observed oxygen-oxygen distance of 2.45 A. This water structure has similarities with hydrated hydroxide found in crystals of certain inorganic complexes. The energy required to displace Dw contributes in significant part to the weak binding of CO(2) in the enzyme-substrate complex, a weak binding that enhances k(cat) for the conversion of CO(2) into bicarbonate. In addition, this short, strong hydrogen bond is expected to contribute to the low pK(a) of the zinc-bound water and to promote proton transfer in catalysis.

A short, strong hydrogen bond in the active site of human carbonic anhydrase II.,Avvaru BS, Kim CU, Sippel KH, Gruner SM, Agbandje-McKenna M, Silverman DN, McKenna R Biochemistry. 2010 Jan 19;49(2):249-51. PMID:20000378<ref>PMID:20000378</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 3ks3" style="background-color:#fffaf0;"></div>

==See Also==
*[[Carbonic anhydrase|Carbonic anhydrase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Carbonate dehydratase]]
[[Category: Human]]
[[Category: Avvaru, B S]]
[[Category: Carbonic anhydrase]]
[[Category: High resolution]]
[[Category: Lyase]]
[[Category: Short hydrogen bond]]