1h4n

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Current revision (06:12, 9 August 2023) (edit) (undo)
 
(20 intermediate revisions not shown.)
Line 1: Line 1:
-
[[Image:1h4n.gif|left|200px]]<br />
 
-
<applet load="1h4n" size="450" color="white" frame="true" align="right" spinBox="true"
 
-
caption="1h4n, resolution 2.0&Aring;" />
 
-
'''H94N CARBONIC ANHYDRASE II COMPLEXED WITH TRIS'''<br />
 
-
==Overview==
+
==H94N CARBONIC ANHYDRASE II COMPLEXED WITH TRIS==
-
The catalytic zinc ion of human carbonic anhydrase II (CAII) is, coordinated by three histidine ligands (H94, H96, and H119) and a, hydroxide ion with tetrahedral geometry. Structural and functional, analysis of variants in which the zinc ligands H94 and H119 are, substituted with asparagine and glutamine, and comparison with results, obtained with aspartate and glutamate substitutions indicate that the, neutral ligand field provided by the protein optimizes the electrostatic, environment for the catalytic function of the metal ion, including, stabilization of bound anions. This is demonstrated by catalytic activity, measurements for ester hydrolysis and CO2 hydration, as well as, sulfonamide inhibitor affinity assays. High-resolution X-ray crystal, structure determinations of H94N, H119N, and H119Q CAIIs reveal that the, engineered carboxamide side chains coordinate to zinc with optimal, stereochemistry. However, zinc coordination geometry remains tetrahedral, only in H119Q CAII. Metal geometry changes to trigonal bipyramidal in, H119N CAII due to the addition of a second water molecule to the zinc, coordination polyhedron and also in H94N CAII due to the displacement of, zinc-bound hydroxide by the bidentate coordination of a Tris molecule., Possibly, the bulky histidine imidazole ligands of the native enzyme play, a role in disfavoring trigonal bipyramidal coordination geometry for zinc., Protein-metal affinity is significantly compromised by all histidine --&gt;, carboxamide ligand substitutions. Diminished affinity may result from, significant movements (up to 1 A) of the metal ion from its position in, the wild-type enzyme, as well as the associated, minor conformational, changes of metal ligands and their neighboring residues.
+
<StructureSection load='1h4n' size='340' side='right'caption='[[1h4n]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
 +
== Structural highlights ==
 +
<table><tr><td colspan='2'>[[1h4n]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1H4N OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1H4N 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]] 2&#8491;</td></tr>
 +
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=TRS:2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>TRS</scene>, <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=1h4n FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1h4n OCA], [https://pdbe.org/1h4n PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1h4n RCSB], [https://www.ebi.ac.uk/pdbsum/1h4n PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1h4n ProSAT]</span></td></tr>
 +
</table>
 +
== Disease ==
 +
[https://www.uniprot.org/uniprot/CAH2_HUMAN CAH2_HUMAN] Defects in CA2 are the cause of osteopetrosis autosomal recessive type 3 (OPTB3) [MIM:[https://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 ==
 +
[https://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/h4/1h4n_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=1h4n ConSurf].
 +
<div style="clear:both"></div>
 +
<div style="background-color:#fffaf0;">
 +
== Publication Abstract from PubMed ==
 +
The catalytic zinc ion of human carbonic anhydrase II (CAII) is coordinated by three histidine ligands (H94, H96, and H119) and a hydroxide ion with tetrahedral geometry. Structural and functional analysis of variants in which the zinc ligands H94 and H119 are substituted with asparagine and glutamine, and comparison with results obtained with aspartate and glutamate substitutions indicate that the neutral ligand field provided by the protein optimizes the electrostatic environment for the catalytic function of the metal ion, including stabilization of bound anions. This is demonstrated by catalytic activity measurements for ester hydrolysis and CO2 hydration, as well as sulfonamide inhibitor affinity assays. High-resolution X-ray crystal structure determinations of H94N, H119N, and H119Q CAIIs reveal that the engineered carboxamide side chains coordinate to zinc with optimal stereochemistry. However, zinc coordination geometry remains tetrahedral only in H119Q CAII. Metal geometry changes to trigonal bipyramidal in H119N CAII due to the addition of a second water molecule to the zinc coordination polyhedron and also in H94N CAII due to the displacement of zinc-bound hydroxide by the bidentate coordination of a Tris molecule. Possibly, the bulky histidine imidazole ligands of the native enzyme play a role in disfavoring trigonal bipyramidal coordination geometry for zinc. Protein-metal affinity is significantly compromised by all histidine --&gt; carboxamide ligand substitutions. Diminished affinity may result from significant movements (up to 1 A) of the metal ion from its position in the wild-type enzyme, as well as the associated, minor conformational changes of metal ligands and their neighboring residues.
-
==About this Structure==
+
Histidine --&gt; carboxamide ligand substitutions in the zinc binding site of carbonic anhydrase II alter metal coordination geometry but retain catalytic activity.,Lesburg CA, Huang C, Christianson DW, Fierke CA Biochemistry. 1997 Dec 16;36(50):15780-91. PMID:9398308<ref>PMID:9398308</ref>
-
1H4N is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with ZN and TRS as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Structure known Active Site: ZN. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1H4N OCA].
+
-
==Reference==
+
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-
Histidine --&gt; carboxamide ligand substitutions in the zinc binding site of carbonic anhydrase II alter metal coordination geometry but retain catalytic activity., Lesburg CA, Huang C, Christianson DW, Fierke CA, Biochemistry. 1997 Dec 16;36(50):15780-91. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9398308 9398308]
+
</div>
-
[[Category: Carbonate dehydratase]]
+
<div class="pdbe-citations 1h4n" style="background-color:#fffaf0;"></div>
-
[[Category: Homo sapiens]]
+
-
[[Category: Single protein]]
+
-
[[Category: Christianson, D.W.]]
+
-
[[Category: Lesburg, C.A.]]
+
-
[[Category: TRS]]
+
-
[[Category: ZN]]
+
-
[[Category: acetylation]]
+
-
[[Category: lyase]]
+
-
[[Category: oxo-acid]]
+
-
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 16:28:37 2007''
+
==See Also==
 +
*[[Carbonic anhydrase 3D structures|Carbonic anhydrase 3D structures]]
 +
== References ==
 +
<references/>
 +
__TOC__
 +
</StructureSection>
 +
[[Category: Homo sapiens]]
 +
[[Category: Large Structures]]
 +
[[Category: Christianson DW]]
 +
[[Category: Lesburg CA]]

Current revision

H94N CARBONIC ANHYDRASE II COMPLEXED WITH TRIS

PDB ID 1h4n

Drag the structure with the mouse to rotate

Proteopedia Page Contributors and Editors (what is this?)

OCA

Personal tools