View source for 8ibk


==Crystal structure of Bacillus sp. AHU2216 GH13_31 Alpha-glucosidase E256Q/N258G in complex with maltotriose==
<StructureSection load='8ibk' size='340' side='right'caption='[[8ibk]], [[Resolution|resolution]] 1.69&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8ibk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_sp._(in:_Bacteria) Bacillus sp. (in: Bacteria)]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8IBK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8IBK 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]] 1.69&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</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=8ibk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8ibk OCA], [https://pdbe.org/8ibk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8ibk RCSB], [https://www.ebi.ac.uk/pdbsum/8ibk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8ibk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A2Z5WH92_BACSP A0A2Z5WH92_BACSP] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
alpha-Glucosidase catalyzes the hydrolysis of alpha-d-glucosides and transglucosylation. Bacillus sp. AHU2216 alpha-glucosidase (BspAG13_31A), belonging to the glycoside hydrolase family 13 subfamily 31, specifically cleaves alpha-(1--&gt;4)-glucosidic linkages and shows high disaccharide specificity. We showed previously that the maltose moiety of maltotriose (G3) and maltotetraose (G4), covering subsites +1 and +2 of BspAG13_31A, adopts a less stable conformation than the global minimum energy conformation. This unstable d-glucosyl conformation likely arises from steric hindrance by Asn258 on beta--&gt;alpha loop 5 of the catalytic (beta/alpha)(8)-barrel. In this study, Asn258 mutants of BspAG13_31A were enzymatically and structurally analyzed. N258G/P mutations significantly enhanced trisaccharide specificity. The N258P mutation also enhanced the activity toward sucrose and produced erlose from sucrose through transglucosylation. N258G showed a higher specificity to transglucosylation with p-nitrophenyl alpha-d-glucopyranoside and maltose than the wild type. E256Q/N258G and E258Q/N258P structures in complex with G3 revealed that the maltose moiety of G3 bound at subsites +1 and +2 adopted a relaxed conformation, whereas a less stable conformation was taken in E256Q. This structural difference suggests that stabilizing the G3 conformation enhances trisaccharide specificity. The E256Q/N258G-G3 complex formed an additional hydrogen bond between Met229 and the d-glucose residue of G3 in subsite +2, and this interaction may enhance transglucosylation.

Alteration of Substrate Specificity and Transglucosylation Activity of GH13_31 alpha-Glucosidase from Bacillus sp. AHU2216 through Site-Directed Mutagenesis of Asn258 on beta--&gt;alpha Loop 5.,Auiewiriyanukul W, Saburi W, Ota T, Yu J, Kato K, Yao M, Mori H Molecules. 2023 Mar 30;28(7):3109. doi: 10.3390/molecules28073109. PMID:37049872<ref>PMID:37049872</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8ibk" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Auiewiriyanukul W]]
[[Category: Kato K]]
[[Category: Mori H]]
[[Category: Saburi W]]
[[Category: Yao M]]
[[Category: Yu J]]