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==Bombyx mori GH13 sucrose hydrolase mutant E322Q covalent intermediate complexed with fructose==
<StructureSection load='6lgi' size='340' side='right'caption='[[6lgi]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6LGI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6LGI 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]] 1.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=BDF:BETA-D-FRUCTOPYRANOSE'>BDF</scene>, <scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=FRU:FRUCTOSE'>FRU</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=6lgi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6lgi OCA], [https://pdbe.org/6lgi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6lgi RCSB], [https://www.ebi.ac.uk/pdbsum/6lgi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6lgi ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
The domestic silkworm Bombyx mori expresses two sucrose-hydrolyzing enzymes, BmSUH and BmSUC1, belonging to glycoside hydrolase family 13 subfamily 17 (GH13_17) and GH32, respectively. BmSUH has little activity on malto-oligosaccharides, whereas other insect GH13_17 alpha-glucosidases are active on sucrose and maltooligosaccharides. Little is currently known about the structural mechanisms and substrate specificity of GH13_17 enzymes. In this study, we examined the crystal structures of BmSUH without ligands; in complexes with substrates, products, and inhibitors; and complexed with its covalent intermediate at 1.60-1.85 A resolutions. These structures revealed that the conformations of amino acid residues around subsite -1 are notably different at each step of the hydrolytic reaction. Such changes have not been previously reported among GH13 enzymes, including exo- and endo-acting hydrolases, such as alpha-glucosidases and alpha-amylases. Amino acid residues at subsite +1 are not conserved in BmSUH and other GH13_17 alpha-glucosidases, but subsite -1 residues are absolutely conserved. Substitutions in three subsite +1 residues, Gln191, Tyr251, and Glu440, decreased sucrose hydrolysis and increased maltase activity of BmSUH, indicating that these residues are key for determining its substrate specificity. These results provide detailed insights into structure-function relationships in GH13 enzymes and into the molecular evolution of insect GH13_17 alpha-glucosidases.

Structure-function analysis of silkworm sucrose hydrolase uncovers the mechanism of substrate specificity in GH13 subfamily 17 exo-alpha-glucosidases.,Miyazaki T, Park EY J Biol Chem. 2020 May 7. pii: RA120.013595. doi: 10.1074/jbc.RA120.013595. PMID:32381508<ref>PMID:32381508</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Miyazaki T]]