1heb: Difference between revisions
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'''STRUCTURAL CONSEQUENCES OF HYDROPHILIC AMINO-ACID SUBSTITUTIONS IN THE HYDROPHOBIC POCKET OF HUMAN CARBONIC ANHYDRASE II''' | {{Structure | ||
|PDB= 1heb |SIZE=350|CAPTION= <scene name='initialview01'>1heb</scene>, resolution 2.0Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> and <scene name='pdbligand=HG:MERCURY (II) ION'>HG</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] | |||
|GENE= | |||
}} | |||
'''STRUCTURAL CONSEQUENCES OF HYDROPHILIC AMINO-ACID SUBSTITUTIONS IN THE HYDROPHOBIC POCKET OF HUMAN CARBONIC ANHYDRASE II''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1HEB is a [ | 1HEB is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HEB OCA]. | ||
==Reference== | ==Reference== | ||
Structural consequences of hydrophilic amino acid substitutions in the hydrophobic pocket of human carbonic anhydrase II., Nair SK, Christianson DW, Biochemistry. 1993 May 4;32(17):4506-14. PMID:[http:// | Structural consequences of hydrophilic amino acid substitutions in the hydrophobic pocket of human carbonic anhydrase II., Nair SK, Christianson DW, Biochemistry. 1993 May 4;32(17):4506-14. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8485129 8485129] | ||
[[Category: Carbonate dehydratase]] | [[Category: Carbonate dehydratase]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
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[[Category: lyase(oxo-acid)]] | [[Category: lyase(oxo-acid)]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:35:59 2008'' | ||
Revision as of 12:36, 20 March 2008
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| , resolution 2.0Å | |||||||
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| Ligands: | and | ||||||
| Activity: | Carbonate dehydratase, with EC number 4.2.1.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STRUCTURAL CONSEQUENCES OF HYDROPHILIC AMINO-ACID SUBSTITUTIONS IN THE HYDROPHOBIC POCKET OF HUMAN CARBONIC ANHYDRASE II
OverviewOverview
The three-dimensional structures of Leu-198-->Glu, Leu-198-->His, Leu-198-->Arg, and Leu-198-->Ala variants of human carbonic anhydrase II (CAII) have each been determined by X-ray crystallographic methods to a resolution of 2.0 A. The side chain of Leu-198 is located at the mouth of the active site hydrophobic pocket, and this pocket is required for substrate association. Hydrophobic-->hydrophilic amino acid substitutions at the mouth of the pocket decrease kcat/KM for CO2 hydration: the CO2 hydrase activities of Leu-198-->Glu, Leu-198-->His, and Leu-198-->Arg CAIIs are diminished 19-fold, 10-fold, and 17-fold, respectively, relative to the wild-type enzyme; however, the substitution of a compact aliphatic side chain for Leu-198 has a smaller effect on catalysis, in that Leu-198-->Ala CAII exhibits only a 3-fold decrease in CO2 hydrase activity [Krebs, J. F., Rana, F., Dluhy, R. A., & Fierke, C. A. (1993) Biochemistry (preceding paper in this issue)]. It is intriguing that CO2 hydrase activity is not severely diminished in Leu-198-->Arg CAII, even though the side chain of Arg-198 blocks the hydrophobic pocket. Therefore, the bulky side chain of Arg-198 must be reasonably mobile in order to accommodate substrate association. Significantly, a residue larger than the wild-type Leu-198 side chain does not necessarily block the substrate association pocket; e.g., the side chain of Glu-198 packs against a hydrophobic patch, the net result of which is a wider mouth for the pocket.(ABSTRACT TRUNCATED AT 250 WORDS)
DiseaseDisease
Known disease associated with this structure: Osteopetrosis, autosomal recessive 3, with renal tubular acidosis OMIM:[611492]
About this StructureAbout this Structure
1HEB is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structural consequences of hydrophilic amino acid substitutions in the hydrophobic pocket of human carbonic anhydrase II., Nair SK, Christianson DW, Biochemistry. 1993 May 4;32(17):4506-14. PMID:8485129
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