View source for 9isa


==Dimeric amylosucrase from Deinococcus geothermalis==
<StructureSection load='9isa' size='340' side='right'caption='[[9isa]], [[Resolution|resolution]] 2.69&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9isa]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Deinococcus_geothermalis_DSM_11300 Deinococcus geothermalis DSM 11300]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9ISA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9ISA 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]] 2.69&#8491;</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=9isa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9isa OCA], [https://pdbe.org/9isa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9isa RCSB], [https://www.ebi.ac.uk/pdbsum/9isa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9isa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q1J0W0_DEIGD Q1J0W0_DEIGD] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Amylosucrase (ASase; E.C. 2.4.1.4), a member of glycoside hydrolase family 13 (GH13), produces alpha-1,4-glucans and sucrose isomers using sucrose as its sole substrate. This study identifies and characterizes the dimeric structure of ASase from Deinococcus geothermalis (DgAS), highlighting essential amino acid residues for maintaining the dimeric state. The monomeric form, DgAS R30A, exhibited a higher affinity for sucrose compared to the wild-type (WT), especially during the formation of the ASase-glucose intermediate complex and subsequent hydrolysis. Notably, DgAS R30A produced a higher proportion of alpha-glucans with a degree of polymerization (DP) of &lt;/=20 and fewer alpha-glucans with a DP of &gt;/=31. This suggested that the reduced surface area of the oligosaccharide binding site in the monomeric form led to decreased binding of longer-chain maltooligosaccharides, favoring the formation of shorter DP alpha-glucans. Kinetic analysis revealed significantly lower Michaelis constants (K(m)) for DgAS R30A's total and hydrolysis activities, with the overall performance (k(cat)/K(m)) values for DgAS R30A exceeded those of the WT at all sucrose concentrations. Here, we report the first high-resolution homodimeric DgAS structure, revealing conserved active site residues and a unique dimerization interface. This study enhances our understanding of the molecular factors influencing the oligomeric state and enzyme activities.

Construction and enzymatic characterization of a monomeric variant of dimeric amylosucrase from Deinococcus geothermalis.,Oh JS, Kim DS, So YS, Hong S, Yoo SH, Park CS, Park JH, Seo DH Int J Biol Macromol. 2025 Jan;285:138249. doi: 10.1016/j.ijbiomac.2024.138249. , Epub 2024 Dec 2. PMID:39631600<ref>PMID:39631600</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9isa" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Deinococcus geothermalis DSM 11300]]
[[Category: Large Structures]]
[[Category: Kim DS]]
[[Category: Park JH]]
[[Category: Seo D]]