View source for 1v3i


==The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase==
<StructureSection load='1v3i' size='340' side='right'caption='[[1v3i]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1v3i]] is a 1 chain structure with sequence from [https://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]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1V3I FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=PRD_900001:alpha-maltose'>PRD_900001</scene>, <scene name='pdbligand=PRD_900018:beta-maltose'>PRD_900018</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1v3i FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1v3i OCA], [https://pdbe.org/1v3i PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1v3i RCSB], [https://www.ebi.ac.uk/pdbsum/1v3i PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1v3i ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/AMYB_SOYBN AMYB_SOYBN] 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/v3/1v3i_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1v3i ConSurf].
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== Publication Abstract from PubMed ==
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.

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<ref>PMID:15178253</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Amylase 3D structures|Amylase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Glycine max]]
[[Category: Large Structures]]
[[Category: Adachi M]]
[[Category: Kang YN]]
[[Category: Mikami B]]
[[Category: Utsumi S]]