View source for 6zjt


==Cold-adapted beta-D-galactosidase from Arthrobacter sp. 32cB mutant E441Q in complex with lactulose==
<StructureSection load='6zjt' size='340' side='right'caption='[[6zjt]], [[Resolution|resolution]] 1.97&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6zjt]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Arthrobacter_sp._32cB Arthrobacter sp. 32cB]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6ZJT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6ZJT 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]] 1.97&#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=FRU:FRUCTOSE'>FRU</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=PRD_900038:lactulose'>PRD_900038</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=6zjt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6zjt OCA], [https://pdbe.org/6zjt PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6zjt RCSB], [https://www.ebi.ac.uk/pdbsum/6zjt PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6zjt ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A023UGN9_9MICC A0A023UGN9_9MICC] 
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== Publication Abstract from PubMed ==
beta-Galactosidase from Arthrobacter sp. 32cB (ArthbetaDG) is a cold-adapted enzyme able to catalyze hydrolysis of beta-d-galactosides and transglycosylation reaction, where galactosyl moiety is being transferred onto an acceptor larger than a water molecule. Mutants of ArthbetaDG: D207A and E517Q were designed to determine the significance of specific residues and to enable formation of complexes with lactulose and sucrose and to shed light onto the structural basis of the transglycosylation reaction. The catalytic assays proved loss of function mutation E517 into glutamine and a significant drop of activity for mutation of D207 into alanine. Solving crystal structures of two new mutants, and new complex structures of previously presented mutant E441Q enables description of introduced changes within active site of enzyme and determining the importance of mutated residues for active site size and character. Furthermore, usage of mutants with diminished and abolished enzymatic activity enabled solving six complex structures with galactose, lactulose or sucrose bounds. As a result, not only the galactose binding sites were mapped on the enzyme's surface but also the mode of lactulose, product of transglycosylation reaction, and binding within the enzyme's active site were determined and the glucopyranose binding site in the distal of active site was discovered. The latter two especially show structural details of transglycosylation, providing valuable information that may be used for engineering of ArthbetaDG or other analogous galactosidases belonging to GH2 family.

Mapping the Transglycosylation Relevant Sites of Cold-Adapted beta-d-Galactosidase from Arthrobacter sp. 32cB.,Rutkiewicz M, Wanarska M, Bujacz A Int J Mol Sci. 2020 Jul 28;21(15). pii: ijms21155354. doi: 10.3390/ijms21155354. PMID:32731412<ref>PMID:32731412</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6zjt" style="background-color:#fffaf0;"></div>

==See Also==
*[[Galactosidase 3D structures|Galactosidase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arthrobacter sp. 32cB]]
[[Category: Large Structures]]
[[Category: Bujacz A]]
[[Category: Bujacz G]]
[[Category: Rutkiewicz M]]