5ca2
From Proteopedia
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|PDB= 5ca2 |SIZE=350|CAPTION= <scene name='initialview01'>5ca2</scene>, resolution 2.1Å | |PDB= 5ca2 |SIZE=350|CAPTION= <scene name='initialview01'>5ca2</scene>, resolution 2.1Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=HG:MERCURY+(II)+ION'>HG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> |
| - | |ACTIVITY= [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] | + | |ACTIVITY= <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> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5ca2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ca2 OCA], [http://www.ebi.ac.uk/pdbsum/5ca2 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=5ca2 RCSB]</span> | ||
}} | }} | ||
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==Overview== | ==Overview== | ||
The three-dimensional structure of the Thr-200----Ser (T200S) mutant of human carbonic anhydrase II (CAII) has been determined by X-ray crystallographic methods at 2.1-A resolution. This particular mutant of CAII exhibits CO2 hydrase activity that is comparable to that of the wild-type enzyme with a 2-fold stabilization of the E.HCO3- complex and esterase activity that is 4-fold greater than that of the wild-type enzyme. The structure of the mutant enzyme reveals no significant local changes accompanying the conservative T200S substitution, but an important nonlocal structural change is evident: the side chain of catalytic residue His-64 rotates away from the active site by 105 degrees about chi 1 and apparently displaces a water molecule. The displaced water molecule is present in the wild-type enzyme; however, the electron density into which this water is built is interpretable as an alternate conformation of His-64 with 10-20% occupancy. The rate constants for proton transfer from the zinc-water ligand to His-64 and from His-64 to bulk solvent are maintained in the T200S variant; therefore, if His-64 is conformationally mobile about chi 1 and/or chi 2 during catalysis, compensatory changes in solvent configuration must sustain efficient proton transfer. | The three-dimensional structure of the Thr-200----Ser (T200S) mutant of human carbonic anhydrase II (CAII) has been determined by X-ray crystallographic methods at 2.1-A resolution. This particular mutant of CAII exhibits CO2 hydrase activity that is comparable to that of the wild-type enzyme with a 2-fold stabilization of the E.HCO3- complex and esterase activity that is 4-fold greater than that of the wild-type enzyme. The structure of the mutant enzyme reveals no significant local changes accompanying the conservative T200S substitution, but an important nonlocal structural change is evident: the side chain of catalytic residue His-64 rotates away from the active site by 105 degrees about chi 1 and apparently displaces a water molecule. The displaced water molecule is present in the wild-type enzyme; however, the electron density into which this water is built is interpretable as an alternate conformation of His-64 with 10-20% occupancy. The rate constants for proton transfer from the zinc-water ligand to His-64 and from His-64 to bulk solvent are maintained in the T200S variant; therefore, if His-64 is conformationally mobile about chi 1 and/or chi 2 during catalysis, compensatory changes in solvent configuration must sustain efficient proton transfer. | ||
| - | |||
| - | ==Disease== | ||
| - | Known disease associated with this structure: Osteopetrosis, autosomal recessive 3, with renal tubular acidosis OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=611492 611492]] | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Alexander, R S.]] | [[Category: Alexander, R S.]] | ||
[[Category: Christianson, D W.]] | [[Category: Christianson, D W.]] | ||
| - | [[Category: HG]] | ||
| - | [[Category: ZN]] | ||
[[Category: lyase(oxo-acid)]] | [[Category: lyase(oxo-acid)]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 05:40:55 2008'' |
Revision as of 02:40, 31 March 2008
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| , resolution 2.1Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Activity: | Carbonate dehydratase, with EC number 4.2.1.1 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CONFORMATIONAL MOBILITY OF HIS-64 IN THE THR-200 (RIGHT ARROW) SER MUTANT OF HUMAN CARBONIC ANHYDRASE II
Overview
The three-dimensional structure of the Thr-200----Ser (T200S) mutant of human carbonic anhydrase II (CAII) has been determined by X-ray crystallographic methods at 2.1-A resolution. This particular mutant of CAII exhibits CO2 hydrase activity that is comparable to that of the wild-type enzyme with a 2-fold stabilization of the E.HCO3- complex and esterase activity that is 4-fold greater than that of the wild-type enzyme. The structure of the mutant enzyme reveals no significant local changes accompanying the conservative T200S substitution, but an important nonlocal structural change is evident: the side chain of catalytic residue His-64 rotates away from the active site by 105 degrees about chi 1 and apparently displaces a water molecule. The displaced water molecule is present in the wild-type enzyme; however, the electron density into which this water is built is interpretable as an alternate conformation of His-64 with 10-20% occupancy. The rate constants for proton transfer from the zinc-water ligand to His-64 and from His-64 to bulk solvent are maintained in the T200S variant; therefore, if His-64 is conformationally mobile about chi 1 and/or chi 2 during catalysis, compensatory changes in solvent configuration must sustain efficient proton transfer.
About this Structure
5CA2 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Conformational mobility of His-64 in the Thr-200----Ser mutant of human carbonic anhydrase II., Krebs JF, Fierke CA, Alexander RS, Christianson DW, Biochemistry. 1991 Sep 24;30(38):9153-60. PMID:1909891
Page seeded by OCA on Mon Mar 31 05:40:55 2008
