1lgd
From Proteopedia
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|PDB= 1lgd |SIZE=350|CAPTION= <scene name='initialview01'>1lgd</scene>, resolution 1.90Å | |PDB= 1lgd |SIZE=350|CAPTION= <scene name='initialview01'>1lgd</scene>, resolution 1.90Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=BCT:BICARBONATE+ION'>BCT</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=[[1lg5|1LG5]], [[1lg6|1LG6]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1lgd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1lgd OCA], [http://www.ebi.ac.uk/pdbsum/1lgd PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1lgd RCSB]</span> | ||
}} | }} | ||
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==Overview== | ==Overview== | ||
Substitution of Pro for Thr199 in the active site of human carbonic anhydrase II (HCA II)(1) reduces its catalytic efficiency about 3000-fold. X-ray crystallographic structures of the T199P/C206S variant have been determined in complex with the substrate bicarbonate and with the inhibitors thiocyanate and beta-mercaptoethanol. The latter molecule is normally not an inhibitor of wild-type HCA II. All three ligands display novel binding interactions to the T199P/C206S mutant. The beta-mercaptoethanol molecule binds in the active site area with its sulfur atom tetrahedrally coordinated to the zinc ion. Thiocyanate binds tetrahedrally coordinated to the zinc ion in T199P/C206S, in contrast to its pentacoordinated binding to the zinc ion in wild-type HCA II. Bicarbonate binds to the mutant with two of its oxygens at the positions of the zinc water (Wat263) and Wat318 in wild-type HCA II. The environment of this area is more hydrophilic than the normal bicarbonate-binding site of HCA II situated in the hydrophobic part of the cavity normally occupied by the so-called deep water (Wat338). The observation of a new binding site for bicarbonate has implications for understanding the mechanism by which the main-chain amino group of Thr199 acquired an important role for orientation of the substrate during the evolution of the enzyme. | Substitution of Pro for Thr199 in the active site of human carbonic anhydrase II (HCA II)(1) reduces its catalytic efficiency about 3000-fold. X-ray crystallographic structures of the T199P/C206S variant have been determined in complex with the substrate bicarbonate and with the inhibitors thiocyanate and beta-mercaptoethanol. The latter molecule is normally not an inhibitor of wild-type HCA II. All three ligands display novel binding interactions to the T199P/C206S mutant. The beta-mercaptoethanol molecule binds in the active site area with its sulfur atom tetrahedrally coordinated to the zinc ion. Thiocyanate binds tetrahedrally coordinated to the zinc ion in T199P/C206S, in contrast to its pentacoordinated binding to the zinc ion in wild-type HCA II. Bicarbonate binds to the mutant with two of its oxygens at the positions of the zinc water (Wat263) and Wat318 in wild-type HCA II. The environment of this area is more hydrophilic than the normal bicarbonate-binding site of HCA II situated in the hydrophobic part of the cavity normally occupied by the so-called deep water (Wat338). The observation of a new binding site for bicarbonate has implications for understanding the mechanism by which the main-chain amino group of Thr199 acquired an important role for orientation of the substrate during the evolution of the enzyme. | ||
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| - | ==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: Sauer-Eriksson, A E.]] | [[Category: Sauer-Eriksson, A E.]] | ||
[[Category: Sjoblom, B.]] | [[Category: Sjoblom, B.]] | ||
| - | [[Category: BCT]] | ||
| - | [[Category: ZN]] | ||
[[Category: hcaii mutant t199p-bct complex]] | [[Category: hcaii mutant t199p-bct complex]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 22:02:30 2008'' |
Revision as of 19:02, 30 March 2008
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| , resolution 1.90Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Activity: | Carbonate dehydratase, with EC number 4.2.1.1 | ||||||
| Related: | 1LG5, 1LG6
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal Structure Analysis of HCA II Mutant T199P in Complex with Bicarbonate
Overview
Substitution of Pro for Thr199 in the active site of human carbonic anhydrase II (HCA II)(1) reduces its catalytic efficiency about 3000-fold. X-ray crystallographic structures of the T199P/C206S variant have been determined in complex with the substrate bicarbonate and with the inhibitors thiocyanate and beta-mercaptoethanol. The latter molecule is normally not an inhibitor of wild-type HCA II. All three ligands display novel binding interactions to the T199P/C206S mutant. The beta-mercaptoethanol molecule binds in the active site area with its sulfur atom tetrahedrally coordinated to the zinc ion. Thiocyanate binds tetrahedrally coordinated to the zinc ion in T199P/C206S, in contrast to its pentacoordinated binding to the zinc ion in wild-type HCA II. Bicarbonate binds to the mutant with two of its oxygens at the positions of the zinc water (Wat263) and Wat318 in wild-type HCA II. The environment of this area is more hydrophilic than the normal bicarbonate-binding site of HCA II situated in the hydrophobic part of the cavity normally occupied by the so-called deep water (Wat338). The observation of a new binding site for bicarbonate has implications for understanding the mechanism by which the main-chain amino group of Thr199 acquired an important role for orientation of the substrate during the evolution of the enzyme.
About this Structure
1LGD is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Organization of an efficient carbonic anhydrase: implications for the mechanism based on structure-function studies of a T199P/C206S mutant., Huang S, Sjoblom B, Sauer-Eriksson AE, Jonsson BH, Biochemistry. 2002 Jun 18;41(24):7628-35. PMID:12056894
Page seeded by OCA on Sun Mar 30 22:02:30 2008
