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| | <StructureSection load='1c7t' size='340' side='right'caption='[[1c7t]], [[Resolution|resolution]] 1.90Å' scene=''> | | <StructureSection load='1c7t' size='340' side='right'caption='[[1c7t]], [[Resolution|resolution]] 1.90Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1c7t]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_marcescens"_(bizio_1823)_trevisan_in_de_toni_and_trevisan_1889 "bacillus marcescens" (bizio 1823) trevisan in de toni and trevisan 1889]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C7T OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1C7T FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1c7t]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Serratia_marcescens Serratia marcescens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C7T OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1C7T FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1qba|1qba]], [[1qbb|1qbb]], [[1qbc|1qbc]], [[1c7s|1c7s]]</div></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Beta-N-acetylhexosaminidase Beta-N-acetylhexosaminidase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.52 3.2.1.52] </span></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=1c7t FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1c7t OCA], [https://pdbe.org/1c7t PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1c7t RCSB], [https://www.ebi.ac.uk/pdbsum/1c7t PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1c7t ProSAT]</span></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=1c7t FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1c7t OCA], [https://pdbe.org/1c7t PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1c7t RCSB], [https://www.ebi.ac.uk/pdbsum/1c7t PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1c7t ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[https://www.uniprot.org/uniprot/CHB_SERMA CHB_SERMA]] Digests the beta-1,4-glycosidic bonds in N-acetylglucosamine (GlcNAc) oligomers (mainly dimers).
| + | [https://www.uniprot.org/uniprot/CHB_SERMA CHB_SERMA] Digests the beta-1,4-glycosidic bonds in N-acetylglucosamine (GlcNAc) oligomers (mainly dimers). |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | *[[Beta-Hexosaminidase|Beta-Hexosaminidase]] | | *[[Beta-Hexosaminidase|Beta-Hexosaminidase]] |
| | *[[Beta-Hexosaminidase 3D structures|Beta-Hexosaminidase 3D structures]] | | *[[Beta-Hexosaminidase 3D structures|Beta-Hexosaminidase 3D structures]] |
| | + | *[[Beta-N-acetylhexosaminidase 3D structures|Beta-N-acetylhexosaminidase 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Beta-N-acetylhexosaminidase]] | |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Oppenheim, A B]] | + | [[Category: Serratia marcescens]] |
| - | [[Category: Papanikolau, Y]] | + | [[Category: Oppenheim AB]] |
| - | [[Category: Petratos, K]] | + | [[Category: Papanikolau Y]] |
| - | [[Category: Prag, G]] | + | [[Category: Petratos K]] |
| - | [[Category: Tavlas, G]] | + | [[Category: Prag G]] |
| - | [[Category: Vorgias, C E]] | + | [[Category: Tavlas G]] |
| - | [[Category: Beta-n-acetylhexosaminidase]]
| + | [[Category: Vorgias CE]] |
| - | [[Category: Chitinolysin]]
| + | |
| - | [[Category: Co-crystal structure]]
| + | |
| - | [[Category: Glycosyl hydrolase]]
| + | |
| - | [[Category: Hydrolase]]
| + | |
| - | [[Category: Proton donor]]
| + | |
| - | [[Category: Site directed mutagenesis]]
| + | |
| Structural highlights
Function
CHB_SERMA Digests the beta-1,4-glycosidic bonds in N-acetylglucosamine (GlcNAc) oligomers (mainly dimers).
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The catalytic domain of chitobiase (beta-N-1-4 acetylhexosaminidase) from Serratia marcescens, is an alpha/beta TIM-barrel. This enzyme belongs to family 20 of glycosyl hydrolases in which a conserved amino acid pair, aspartate-glutamate, is present (Asp539-Glu540). It was proposed that catalysis by this enzyme family is carried out by glutamate 540 acting as a proton donor and by the acetamido group of the substrate as a nucleophile. We investigated the role of Asp539 and Glu540 by site-directed mutagenesis, biochemical characterization and by structural analyses of chitobiase -substrate co-crystals. We found that both residues are essential for chitobiase activity. The mutations, however, led to subtle changes in the catalytic site. Our results support the model that Glu540 acts as the proton donor and that Asp539 acts in several different ways. Asp539 restrains the acetamido group of the substrate in a specific orientation by forming a hydrogen bond with N2 of the non-reduced (-1) sugar. In addition, this residue participates in substrate binding. It is also required for the correct positioning of Glu540 and may provide additional negative charge at the active site. Thus, these biochemical and structural studies provide a molecular explanation for the functional importance and conservation of these residues.
Structures of chitobiase mutants complexed with the substrate Di-N-acetyl-d-glucosamine: the catalytic role of the conserved acidic pair, aspartate 539 and glutamate 540.,Prag G, Papanikolau Y, Tavlas G, Vorgias CE, Petratos K, Oppenheim AB J Mol Biol. 2000 Jul 14;300(3):611-7. PMID:10884356[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Prag G, Papanikolau Y, Tavlas G, Vorgias CE, Petratos K, Oppenheim AB. Structures of chitobiase mutants complexed with the substrate Di-N-acetyl-d-glucosamine: the catalytic role of the conserved acidic pair, aspartate 539 and glutamate 540. J Mol Biol. 2000 Jul 14;300(3):611-7. PMID:10884356 doi:10.1006/jmbi.2000.3906
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