4c7g: Difference between revisions
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== | ==Structure and activity of the GH20 beta-N-acetylhexosaminidase from Streptomyces coelicolor A3(2)== | ||
[[4c7g]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4C7G OCA]. | <StructureSection load='4c7g' size='340' side='right'caption='[[4c7g]], [[Resolution|resolution]] 1.80Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4c7g]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_coelicolor Streptomyces coelicolor]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4C7G OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4C7G 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]] 1.8Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=NGO:2-METHYL-4,5-DIHYDRO-(1,2-DIDEOXY-ALPHA-D-GLUCOPYRANOSO)[2,1-D]-1,3-OXAZOLE'>NGO</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=4c7g FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4c7g OCA], [https://pdbe.org/4c7g PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4c7g RCSB], [https://www.ebi.ac.uk/pdbsum/4c7g PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4c7g ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/Q9L068_STRCO Q9L068_STRCO] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
beta-N-acetylhexosaminidases (HEX) are glycosidases that catalyze the glycosidic linkage hydrolysis of gluco- and galacto-configured N-acetyl-beta-D-hexosaminides. These enzymes are important in human physiology and are candidates for the biocatalytic production of carbohydrates and glycomimetics. In this study, the three-dimensional structure of the wild-type and catalytically impaired E302Q HEX variant from the soil bacterium Streptomyces coelicolor A3(2) (ScHEX) were solved in ligand-free forms and in the presence of 6-acetamido-6-deoxy-castanospermine (6-Ac-Cas). The E302Q variant was also trapped as an intermediate with oxazoline bound to the active center. Crystallographic evidence highlights structural variations in the loop 3 environment, suggesting conformational heterogeneity for important active-site residues of this GH20 family member. The enzyme was investigated for its beta-N-acetylhexosaminidase activity toward chitooligomers and pNP-acetyl gluco- and galacto-configured N-acetyl hexosaminides. Kinetic analyses confirm the beta(1-4) glycosidic linkage substrate preference and HPLC profiles support an exoglycosidase mechanism, where the enzyme cleaves sugars from the non-reducing end of substrates. ScHEX possesses significant activity toward chitooligosaccharides of varying degrees of polymerization and the final hydrolytic reaction yielded pure GlcNAc without any byproduct, promising high applicability for the enzymatic production of this highly valued chemical. Thermostability and activation assays further suggest efficient conditions applicable to the enzymatic production of GlcNAc from chitooligomers. | |||
Structure and activity of the Streptomyces coelicolor A3(2) beta-N-acetylhexosaminidase provides further insight into GH20 family catalysis and inhibition.,Nguyen Thi N, Offen WA, Shareck F, Davies GJ, Doucet N Biochemistry. 2014 Feb 21. PMID:24559145<ref>PMID:24559145</ref> | |||
<ref | |||
[[ | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | |||
<div class="pdbe-citations 4c7g" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Beta-N-acetylhexosaminidase 3D structures|Beta-N-acetylhexosaminidase 3D structures]] | |||
== References == | |||
<references/> | |||
[[Category: | __TOC__ | ||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Streptomyces coelicolor]] | [[Category: Streptomyces coelicolor]] | ||
[[Category: Davies GJ]] | |||
[[Category: Doucet N]] | |||
[[Category: Nguyenthi N]] | |||
[[Category: Offen WA]] | |||
Latest revision as of 15:05, 20 December 2023
Structure and activity of the GH20 beta-N-acetylhexosaminidase from Streptomyces coelicolor A3(2)Structure and activity of the GH20 beta-N-acetylhexosaminidase from Streptomyces coelicolor A3(2)
Structural highlights
FunctionPublication Abstract from PubMedbeta-N-acetylhexosaminidases (HEX) are glycosidases that catalyze the glycosidic linkage hydrolysis of gluco- and galacto-configured N-acetyl-beta-D-hexosaminides. These enzymes are important in human physiology and are candidates for the biocatalytic production of carbohydrates and glycomimetics. In this study, the three-dimensional structure of the wild-type and catalytically impaired E302Q HEX variant from the soil bacterium Streptomyces coelicolor A3(2) (ScHEX) were solved in ligand-free forms and in the presence of 6-acetamido-6-deoxy-castanospermine (6-Ac-Cas). The E302Q variant was also trapped as an intermediate with oxazoline bound to the active center. Crystallographic evidence highlights structural variations in the loop 3 environment, suggesting conformational heterogeneity for important active-site residues of this GH20 family member. The enzyme was investigated for its beta-N-acetylhexosaminidase activity toward chitooligomers and pNP-acetyl gluco- and galacto-configured N-acetyl hexosaminides. Kinetic analyses confirm the beta(1-4) glycosidic linkage substrate preference and HPLC profiles support an exoglycosidase mechanism, where the enzyme cleaves sugars from the non-reducing end of substrates. ScHEX possesses significant activity toward chitooligosaccharides of varying degrees of polymerization and the final hydrolytic reaction yielded pure GlcNAc without any byproduct, promising high applicability for the enzymatic production of this highly valued chemical. Thermostability and activation assays further suggest efficient conditions applicable to the enzymatic production of GlcNAc from chitooligomers. Structure and activity of the Streptomyces coelicolor A3(2) beta-N-acetylhexosaminidase provides further insight into GH20 family catalysis and inhibition.,Nguyen Thi N, Offen WA, Shareck F, Davies GJ, Doucet N Biochemistry. 2014 Feb 21. PMID:24559145[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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