1q4n
From Proteopedia
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|PDB= 1q4n |SIZE=350|CAPTION= <scene name='initialview01'>1q4n</scene>, resolution 2.07Å | |PDB= 1q4n |SIZE=350|CAPTION= <scene name='initialview01'>1q4n</scene>, resolution 2.07Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene> | + | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene>, <scene name='pdbligand=TAM:TRIS(HYDROXYETHYL)AMINOMETHANE'>TAM</scene> |
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] </span> |
|GENE= AMY1A OR AMY1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]) | |GENE= AMY1A OR AMY1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1q4n FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1q4n OCA], [http://www.ebi.ac.uk/pdbsum/1q4n PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1q4n RCSB]</span> | ||
}} | }} | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Ramasubbu, N.]] | [[Category: Ramasubbu, N.]] | ||
| - | [[Category: CA]] | ||
| - | [[Category: CL]] | ||
| - | [[Category: TAM]] | ||
[[Category: amylase]] | [[Category: amylase]] | ||
[[Category: inhibitor]] | [[Category: inhibitor]] | ||
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[[Category: tri]] | [[Category: tri]] | ||
| - | ''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 23:08:42 2008'' |
Revision as of 20:08, 30 March 2008
| |||||||
| , resolution 2.07Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , , | ||||||
| Gene: | AMY1A OR AMY1 (Homo sapiens) | ||||||
| Activity: | Alpha-amylase, with EC number 3.2.1.1 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structural studies of Phe256Trp of human salivary alpha-amylase: implications for the role of a conserved water molecule and its associated chain in enzyme activity
Overview
In the mechanism of hydrolysis of starch by alpha-amylases, a conserved water molecule bridging two catalytic residues has been implicated. In human salivary alpha-amylase (HSAmy), this water (W641), observed in many alpha-amylase structures, is part of a chain of water molecules. To test the hypothesis that W641 may be involved in the mechanism, Phe256 in the close vicinity was mutated to a Trp residue. X-ray structure of F256W complexed to 2-amino-2-(hydroxyethyl)-1,3-propanediol at 2.1A revealed that the water chain is disrupted. In the F256W structure exhibits a positional shift in His305, characteristic of alpha-amylase complex structures. Kinetic analysis, in comparison with HSAmy, revealed that the mutant exhibited a 70-fold decrease in the specific activity for starch and significantly reduced k(cat) (20-fold) and K(m) (4-fold) for maltoheptaoside. Collectively, these results suggest that W641 and the chain of water molecules may be critical for the alpha-amylase activity.
About this Structure
1Q4N is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structural studies of a Phe256Trp mutant of human salivary alpha-amylase: implications for the role of a conserved water molecule in enzyme activity., Ramasubbu N, Sundar K, Ragunath C, Rafi MM, Arch Biochem Biophys. 2004 Jan 1;421(1):115-24. PMID:14678792
Page seeded by OCA on Sun Mar 30 23:08:42 2008
Categories: Alpha-amylase | Homo sapiens | Single protein | Ramasubbu, N. | Amylase | Inhibitor | Mutagenesis | Tri
