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| | ==Crystal structure of single mutant thermostable endoglucanase (D468A) from Alicyclobacillus acidocaldarius== | | ==Crystal structure of single mutant thermostable endoglucanase (D468A) from Alicyclobacillus acidocaldarius== |
| - | <StructureSection load='5e2j' size='340' side='right' caption='[[5e2j]], [[Resolution|resolution]] 2.10Å' scene=''> | + | <StructureSection load='5e2j' size='340' side='right'caption='[[5e2j]], [[Resolution|resolution]] 2.10Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5e2j]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Aliac Aliac]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5E2J OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5E2J FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5e2j]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Alicyclobacillus_acidocaldarius_subsp._acidocaldarius Alicyclobacillus acidocaldarius subsp. acidocaldarius]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5E2J OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5E2J FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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]] 2.1Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">celA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1388 ALIAC])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] </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=5e2j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5e2j OCA], [https://pdbe.org/5e2j PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5e2j RCSB], [https://www.ebi.ac.uk/pdbsum/5e2j PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5e2j ProSAT]</span></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5e2j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5e2j OCA], [http://pdbe.org/5e2j PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5e2j RCSB], [http://www.ebi.ac.uk/pdbsum/5e2j PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5e2j ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/Q9AJS0_ALIAC Q9AJS0_ALIAC] |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Aliac]] | + | [[Category: Alicyclobacillus acidocaldarius subsp. acidocaldarius]] |
| - | [[Category: Cellulase]] | + | [[Category: Large Structures]] |
| - | [[Category: Hsiao, Y Y]] | + | [[Category: Hsiao YY]] |
| - | [[Category: Tseng, C P]] | + | [[Category: Tseng CP]] |
| - | [[Category: Wang, H J]] | + | [[Category: Wang HJ]] |
| - | [[Category: Endoglucanase]]
| + | |
| - | [[Category: Cellulose hydrolase beta-1]]
| + | |
| - | [[Category: Hydrolase]]
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| Structural highlights
Function
Q9AJS0_ALIAC
Publication Abstract from PubMed
Structural calcium sites control protein thermostability and activity by stabilizing native folds and changing local conformations. Alicyclobacillus acidocaldarius survives in thermal-acidic conditions and produces an endoglucanase Cel9A (AaCel9A), which contains a calcium-binding site (Ser465-Val470) near the catalytic cleft. By superimposing the Ca2+-free and Ca2+-bounded conformations of the calcium site, we found that Ca2+ induces hydrophobic interactions between the calcium site and its nearby region by driving a conformational change. The hydrophobic interactions at the high B-factor region could be enhanced further by replacing the surrounding polar residues to hydrophobic residues in turn to affect enzyme thermostability and activity. Therefore, the calcium-binding residue Asp468, whose side chain directly ligates Ca2+, along with Asp469 and Asp471 of AaCel9A, were separately replaced by alanine and valine. Mutants D468A and D468V showed increased activity compared with those of wild type at 0 mM or 10 mM Ca2+; whereas the Asp469 or Asp471 substitutions resulted in decreased activity. The D468A crystal structure revealed that mutation D468A triggered a conformational change similar to that induced by Ca2+ in wild type and developed a hydrophobic interaction network between the calcium site and the neighboring hydrophobic region (Ala113-Ala117). Mutations D468V and D468A increased 4.5 degrees C and 5.9 degrees C in melting temperature, respectively; and enzyme half-life at 75 degrees C increased approximately 13 times. Structural comparisons between AaCel9A and other endoglucanases of GH9 family suggested that the stability of the regions corresponding to the AaCel9A calcium site plays an important role in GH9 endoglucanase catalysis at high temperature.
Polarity Alteration of Calcium Site Induces a Hydrophobic Interaction Network and Enhances Cel9A Endoglucanase Thermostability.,Wang HJ, Hsiao YY, Chen YP, Ma TY, Tseng CP Appl Environ Microbiol. 2016 Jan 4. pii: AEM.03326-15. PMID:26729722[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Wang HJ, Hsiao YY, Chen YP, Ma TY, Tseng CP. Polarity Alteration of Calcium Site Induces a Hydrophobic Interaction Network and Enhances Cel9A Endoglucanase Thermostability. Appl Environ Microbiol. 2016 Jan 4. pii: AEM.03326-15. PMID:26729722 doi:http://dx.doi.org/10.1128/AEM.03326-15
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