1kgu: Difference between revisions
No edit summary |
No edit summary |
||
| Line 3: | Line 3: | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1kgu]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KGU OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1KGU FirstGlance]. <br> | <table><tr><td colspan='2'>[[1kgu]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KGU OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1KGU FirstGlance]. <br> | ||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>< | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr> | ||
<tr><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene></td></tr> | <tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene></td></tr> | ||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1bs1|1bs1]], [[1kb3|1kb3]], [[1kgw|1kgw]], [[1kgx|1kgx]]</td></tr> | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1bs1|1bs1]], [[1kb3|1kb3]], [[1kgw|1kgw]], [[1kgx|1kgx]]</td></tr> | ||
<tr><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><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1kgu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kgu OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1kgu RCSB], [http://www.ebi.ac.uk/pdbsum/1kgu 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=1kgu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kgu OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1kgu RCSB], [http://www.ebi.ac.uk/pdbsum/1kgu PDBsum]</span></td></tr> | ||
<table> | </table> | ||
== Evolutionary Conservation == | == Evolutionary Conservation == | ||
[[Image:Consurf_key_small.gif|200px|right]] | [[Image:Consurf_key_small.gif|200px|right]] | ||
| Line 30: | Line 30: | ||
==See Also== | ==See Also== | ||
*[[Amylase|Amylase]] | *[[Amylase|Amylase]] | ||
*[[User:Gabriel Pons/Sandbox 2|User:Gabriel Pons/Sandbox 2]] | |||
== References == | == References == | ||
<references/> | <references/> | ||
| Line 36: | Line 37: | ||
[[Category: Alpha-amylase]] | [[Category: Alpha-amylase]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Brayer, G D | [[Category: Brayer, G D]] | ||
[[Category: Maurus, R | [[Category: Maurus, R]] | ||
[[Category: Numao, S | [[Category: Numao, S]] | ||
[[Category: Overall, C M | [[Category: Overall, C M]] | ||
[[Category: Sidhu, G | [[Category: Sidhu, G]] | ||
[[Category: Wang, Y | [[Category: Wang, Y]] | ||
[[Category: Withers, S G | [[Category: Withers, S G]] | ||
[[Category: Catalysis]] | [[Category: Catalysis]] | ||
[[Category: Chloride binding]] | [[Category: Chloride binding]] | ||
Revision as of 19:53, 5 January 2015
THREE DIMENSIONAL STRUCTURE ANALYSIS OF THE R337A VARIANT OF HUMAN PANCREATIC ALPHA-AMYLASETHREE DIMENSIONAL STRUCTURE ANALYSIS OF THE R337A VARIANT OF HUMAN PANCREATIC 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 PubMedHuman pancreatic alpha-amylase (HPA) is a member of the alpha-amylase family involved in the degradation of starch. Some members of this family, including HPA, require chloride for maximal activity. To determine the mechanism of chloride activation, a series of mutants (R195A, R195Q, N298S, R337A, and R337Q) were made in which residues in the chloride ion binding site were replaced. Mutations in this binding site were found to severely affect the ability of HPA to bind chloride ions with no binding detected for the R195 and R337 mutant enzymes. X-ray crystallographic analysis revealed that these mutations did not result in significant structural changes. However, the introduction of these mutations did alter the kinetic properties of the enzyme. Mutations to residue R195 resulted in a 20-450-fold decrease in the activity of the enzyme toward starch and shifted the pH optimum to a more basic pH. Interestingly, replacement of R337 with a nonbasic amino acid resulted in an alpha-amylase that no longer required chloride for catalysis and has a pH profile similar to that of wild-type HPA. In contrast, a mutation at residue N298 resulted in an enzyme that had much lower binding affinity for chloride but still required chloride for maximal activity. We propose that the chloride is required to increase the pK(a) of the acid/base catalyst, E233, which would otherwise be lower due to the presence of R337, a positively charged residue. Probing the role of the chloride ion in the mechanism of human pancreatic alpha-amylase.,Numao S, Maurus R, Sidhu G, Wang Y, Overall CM, Brayer GD, Withers SG Biochemistry. 2002 Jan 8;41(1):215-25. PMID:11772019[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
| ||||||||||||||||||||||