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==CRYSTAL STRUCTURE ANALYSIS OF THE MUTANT K300Q OF PSEUDOALTEROMONAS HALOPLANCTIS ALPHA-AMYLASE== | ==CRYSTAL STRUCTURE ANALYSIS OF THE MUTANT K300Q OF PSEUDOALTEROMONAS HALOPLANCTIS ALPHA-AMYLASE== | ||
<StructureSection load='1jd9' size='340' side='right' caption='[[1jd9]], [[Resolution|resolution]] 2.50Å' scene=''> | <StructureSection load='1jd9' size='340' side='right' caption='[[1jd9]], [[Resolution|resolution]] 2.50Å' scene=''> | ||
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<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">AMY ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=228 "Alteromonas marinopraesens" (ZoBell and Upham 1944) Baumann et al. 1972])</td></tr> | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">AMY ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=228 "Alteromonas marinopraesens" (ZoBell and Upham 1944) Baumann et al. 1972])</td></tr> | ||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] </span></td></tr> | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] </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=1jd9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jd9 OCA], [http://pdbe.org/1jd9 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1jd9 RCSB], [http://www.ebi.ac.uk/pdbsum/1jd9 PDBsum]</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=1jd9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jd9 OCA], [http://pdbe.org/1jd9 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1jd9 RCSB], [http://www.ebi.ac.uk/pdbsum/1jd9 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1jd9 ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Evolutionary Conservation == | == Evolutionary Conservation == | ||
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Check<jmol> | Check<jmol> | ||
<jmolCheckbox> | <jmolCheckbox> | ||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/jd/1jd9_consurf.spt"</scriptWhenChecked> | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/jd/1jd9_consurf.spt"</scriptWhenChecked> | ||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | ||
<text>to colour the structure by Evolutionary Conservation</text> | <text>to colour the structure by Evolutionary Conservation</text> | ||
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</div> | </div> | ||
<div class="pdbe-citations 1jd9" style="background-color:#fffaf0;"></div> | <div class="pdbe-citations 1jd9" style="background-color:#fffaf0;"></div> | ||
== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 12:13, 17 January 2018
CRYSTAL STRUCTURE ANALYSIS OF THE MUTANT K300Q OF PSEUDOALTEROMONAS HALOPLANCTIS ALPHA-AMYLASECRYSTAL STRUCTURE ANALYSIS OF THE MUTANT K300Q OF PSEUDOALTEROMONAS HALOPLANCTIS ALPHA-AMYLASE
Structural highlights
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 PubMedTo further investigate the mechanism and function of allosteric activation by chloride in some alpha-amylases, the structure of the bacterial alpha-amylase from the psychrophilic micro-organism Pseudoalteromonas haloplanktis in complex with nitrate has been solved at 2.1 A degrees, as well as the structure of the mutants Lys300Gln (2.5 A degrees ) and Lys300Arg (2.25 A degrees ). Nitrate binds strongly to alpha-amylase but is a weak activator. Mutation of the critical chloride ligand Lys300 into Gln results in a chloride-independent enzyme, whereas the mutation into Arg mimics the binding site as is found in animal alpha-amylases with, however, a lower affinity for chloride. These structures reveal that the triangular conformation of the chloride ligands and the nearly equatorial coordination allow the perfect accommodation of planar trigonal monovalent anions such as NO3-, explaining their unusual strong binding. It is also shown that a localized negative charge such as that of Cl-, rather than a delocalized charge as in the case of nitrate, is essential for maximal activation. The chloride-free mutant Lys300Gln indicates that chloride is not mandatory for the catalytic mechanism but strongly increases the reactivity at the active site. Disappearance of the putative catalytic water molecule in this weakly active mutant supports the view that chloride helps to polarize the hydrolytic water molecule and enhances the rate of the second step in the catalytic reaction. Structural basis of alpha-amylase activation by chloride.,Aghajari N, Feller G, Gerday C, Haser R Protein Sci. 2002 Jun;11(6):1435-41. PMID:12021442[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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