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[[Image: | ==CRYSTAL STRUCTURE OF PHOSPHOSERINE AMINOTRANSFERASE FROM BACILLUS CIRCULANS VAR. ALKALOPHILUS AT PH 8.5== | ||
<StructureSection load='2c0r' size='340' side='right' caption='[[2c0r]], [[Resolution|resolution]] 1.20Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2c0r]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2C0R OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2C0R FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1bt4|1bt4]], [[1w3u|1w3u]]</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Phosphoserine_transaminase Phosphoserine transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.52 2.6.1.52] </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=2c0r FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2c0r OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2c0r RCSB], [http://www.ebi.ac.uk/pdbsum/2c0r PDBsum]</span></td></tr> | |||
<table> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/c0/2c0r_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
pH is one of the key parameters that affect the stability and function of proteins. We have studied the effect of pH on the pyridoxal-5'-phosphate-dependent enzyme phosphoserine aminotransferase produced by the facultative alkaliphile Bacillus circulans ssp. alkalophilus using thermodynamic and crystallographic analysis. Enzymatic activity assay showed that the enzyme has maximum activity at pH 9.0 and relative activity less than 10% at pH 7.0. Differential scanning calorimetry and circular dichroism experiments revealed variations in the stability and denaturation profiles of the enzyme at different pHs. Most importantly, release of pyridoxal-5'-phosphate and protein thermal denaturation were found to occur simultaneously at pH 6.0 in contrast to pH 8.5 where denaturation preceded cofactor's release by approximately 3 degrees C. To correlate the observed differences in thermal denaturation with structural features, the crystal structure of phosphoserine aminotransferase was determined at 1.2 and 1.5 A resolution at two different pHs (8.5 and 4.6, respectively). Analysis of the two structures revealed changes in the vicinity of the active site and in surface residues. A conformational change in a loop involved in substrate binding at the entrance of the active site has been identified upon pH change. Moreover, the number of intramolecular ion pairs was found reduced in the pH 4.6 structure. Taken together, the presented kinetics, thermal denaturation, and crystallographic data demonstrate a potential role of the active site in unfolding and suggest that subtle but structurally significant conformational rearrangements are involved in the stability and integrity of phosphoserine aminotransferase in response to pH changes. | |||
Effect of pH on the structure and stability of Bacillus circulans ssp. alkalophilus phosphoserine aminotransferase: thermodynamic and crystallographic studies.,Kapetaniou EG, Thanassoulas A, Dubnovitsky AP, Nounesis G, Papageorgiou AC Proteins. 2006 Jun 1;63(4):742-53. PMID:16532449<ref>PMID:16532449</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Phosphoserine aminotransferase|Phosphoserine aminotransferase]] | *[[Phosphoserine aminotransferase|Phosphoserine aminotransferase]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Bacillus circulans]] | [[Category: Bacillus circulans]] | ||
[[Category: Phosphoserine transaminase]] | [[Category: Phosphoserine transaminase]] | ||
Revision as of 06:43, 29 September 2014
CRYSTAL STRUCTURE OF PHOSPHOSERINE AMINOTRANSFERASE FROM BACILLUS CIRCULANS VAR. ALKALOPHILUS AT PH 8.5CRYSTAL STRUCTURE OF PHOSPHOSERINE AMINOTRANSFERASE FROM BACILLUS CIRCULANS VAR. ALKALOPHILUS AT PH 8.5
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 PubMedpH is one of the key parameters that affect the stability and function of proteins. We have studied the effect of pH on the pyridoxal-5'-phosphate-dependent enzyme phosphoserine aminotransferase produced by the facultative alkaliphile Bacillus circulans ssp. alkalophilus using thermodynamic and crystallographic analysis. Enzymatic activity assay showed that the enzyme has maximum activity at pH 9.0 and relative activity less than 10% at pH 7.0. Differential scanning calorimetry and circular dichroism experiments revealed variations in the stability and denaturation profiles of the enzyme at different pHs. Most importantly, release of pyridoxal-5'-phosphate and protein thermal denaturation were found to occur simultaneously at pH 6.0 in contrast to pH 8.5 where denaturation preceded cofactor's release by approximately 3 degrees C. To correlate the observed differences in thermal denaturation with structural features, the crystal structure of phosphoserine aminotransferase was determined at 1.2 and 1.5 A resolution at two different pHs (8.5 and 4.6, respectively). Analysis of the two structures revealed changes in the vicinity of the active site and in surface residues. A conformational change in a loop involved in substrate binding at the entrance of the active site has been identified upon pH change. Moreover, the number of intramolecular ion pairs was found reduced in the pH 4.6 structure. Taken together, the presented kinetics, thermal denaturation, and crystallographic data demonstrate a potential role of the active site in unfolding and suggest that subtle but structurally significant conformational rearrangements are involved in the stability and integrity of phosphoserine aminotransferase in response to pH changes. Effect of pH on the structure and stability of Bacillus circulans ssp. alkalophilus phosphoserine aminotransferase: thermodynamic and crystallographic studies.,Kapetaniou EG, Thanassoulas A, Dubnovitsky AP, Nounesis G, Papageorgiou AC Proteins. 2006 Jun 1;63(4):742-53. PMID:16532449[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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