1v3i: Difference between revisions
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'''The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase''' | {{Structure | ||
|PDB= 1v3i |SIZE=350|CAPTION= <scene name='initialview01'>1v3i</scene>, resolution 1.90Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=SO4:SULFATE ION'>SO4</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Beta-amylase Beta-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.2 3.2.1.2] | |||
|GENE= BMY1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3847 Glycine max]) | |||
}} | |||
'''The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1V3I is a [ | 1V3I is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Glycine_max Glycine max]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V3I OCA]. | ||
==Reference== | ==Reference== | ||
The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase., Kang YN, Adachi M, Utsumi S, Mikami B, J Mol Biol. 2004 Jun 18;339(5):1129-40. PMID:[http:// | The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase., Kang YN, Adachi M, Utsumi S, Mikami B, J Mol Biol. 2004 Jun 18;339(5):1129-40. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15178253 15178253] | ||
[[Category: Beta-amylase]] | [[Category: Beta-amylase]] | ||
[[Category: Glycine max]] | [[Category: Glycine max]] | ||
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[[Category: (beta/alpha)8 barrel]] | [[Category: (beta/alpha)8 barrel]] | ||
''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 14:40:20 2008'' | ||
Revision as of 15:40, 20 March 2008
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| , resolution 1.90Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Gene: | BMY1 (Glycine max) | ||||||
| Activity: | Beta-amylase, with EC number 3.2.1.2 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase
OverviewOverview
It has previously been suggested that the glutamic acid residues Glu186 and Glu380 of soybean beta-amylase play critical roles as a general acid and a general base catalyst, respectively. In order to confirm the roles of Glu186 and Glu380, each residue was mutated to a glutamine residue and the crystal structures of the substrate (E186Q/maltopentaose) and product (E380Q/maltose) complexes were determined at resolutions of 1.6 Angstrom and 1.9 Angstrom, respectively. Both mutant enzymes exhibited 16,000- and 37,000-fold decreased activity relative to that of the wild-type enzyme. The crystal structure of the E186Q/maltopentaose complex revealed an unambiguous five-glucose unit at subsites -2 to +3. Two maltose molecules bind on subsites -2 to -1 and +2 to +3 in the E380Q/maltose complex, whereas they bind in tandem to -2 to -1 and +1 to +2 in the wild-type/maltose complex. The conformation of the glucose residue at subsite -1 was identified as a stable (4)C(1) alpha-anomer in the E380Q/maltose complex, whereas a distorted ring conformation was observed in the wild-type/maltose complex. The side-chain movement of Gln380 to the position of a putative attacking water molecule seen in the wild-type enzyme caused the inactivation of the E380Q mutant and an altered binding pattern of maltose molecules. These results confirm the critical roles played by Glu186 in the donation of a proton to the glycosidic oxygen of the substrate, and by Glu380 in the activation of an attacking water molecule. The observed difference between the backbones of E186Q/maltopentaose and E380Q/maltose in terms of Thr342 suggests that the side-chain of Thr342 may stabilize the deprotonated form of Glu186 after the cleavage of the glycosidic bond.
About this StructureAbout this Structure
1V3I is a Single protein structure of sequence from Glycine max. Full crystallographic information is available from OCA.
ReferenceReference
The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase., Kang YN, Adachi M, Utsumi S, Mikami B, J Mol Biol. 2004 Jun 18;339(5):1129-40. PMID:15178253
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