<it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship

<p>Abstract</p> <p>Background</p> <p>Presence of phosphorylated Serine biosynthesis pathway upstream to the de novo cysteine biosynthesis pathway makes PSAT a crucial enzyme. Besides this, phoshoserine produced by the enzyme can also be taken up directly by cysteine syn...

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Main Authors: Bhakuni Vinod, Nozaki Tomoyoshi, Ali Vahab, Mishra Vibhor
Format: Article
Language:English
Published: BMC 2010-03-01
Series:BMC Research Notes
Online Access:http://www.biomedcentral.com/1756-0500/3/52
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author Bhakuni Vinod
Nozaki Tomoyoshi
Ali Vahab
Mishra Vibhor
author_facet Bhakuni Vinod
Nozaki Tomoyoshi
Ali Vahab
Mishra Vibhor
author_sort Bhakuni Vinod
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Presence of phosphorylated Serine biosynthesis pathway upstream to the de novo cysteine biosynthesis pathway makes PSAT a crucial enzyme. Besides this, phoshoserine produced by the enzyme can also be taken up directly by cysteine synthase as a substrate. PSAT is a PLP dependent enzyme where the cofactor serves as an epicenter for functional catalysis with the active site architecture playing crucial role in optimum function of the enzyme.</p> <p>Findings</p> <p>EhPSAT is a homodimer of molecular mass 86 kDa. To understand the structural modulations associated with pH dependent changes in functional activity of EhPSAT detailed biophysical studies were carried out. pH alterations had no significant effect on the secondary structure, cofactor orientation and oligomeric configuration of the enzyme however, pH dependent compaction in molecular dimensions was observed. Most interestingly, a direct correlation between pH induced modulation of functional activity and orientation of Trp 101 present in the active site of the enzyme was observed. Sodium halides nullified the pH induced global changes in the enzyme, however differential effect of these salts on the active site microenvironment and functional activity of the enzyme was observed.</p> <p>Conclusions</p> <p>The study unequivocally demonstrates that pH induced selective modification of active site microenvironment and not global change in structure or oligomeric status of the enzyme is responsible for the pH dependent change in enzymatic activity of PSAT.</p>
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spelling doaj.art-b736cd8b2a9149159fbede6191189c602022-12-22T01:35:59ZengBMCBMC Research Notes1756-05002010-03-01315210.1186/1756-0500-3-52<it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationshipBhakuni VinodNozaki TomoyoshiAli VahabMishra Vibhor<p>Abstract</p> <p>Background</p> <p>Presence of phosphorylated Serine biosynthesis pathway upstream to the de novo cysteine biosynthesis pathway makes PSAT a crucial enzyme. Besides this, phoshoserine produced by the enzyme can also be taken up directly by cysteine synthase as a substrate. PSAT is a PLP dependent enzyme where the cofactor serves as an epicenter for functional catalysis with the active site architecture playing crucial role in optimum function of the enzyme.</p> <p>Findings</p> <p>EhPSAT is a homodimer of molecular mass 86 kDa. To understand the structural modulations associated with pH dependent changes in functional activity of EhPSAT detailed biophysical studies were carried out. pH alterations had no significant effect on the secondary structure, cofactor orientation and oligomeric configuration of the enzyme however, pH dependent compaction in molecular dimensions was observed. Most interestingly, a direct correlation between pH induced modulation of functional activity and orientation of Trp 101 present in the active site of the enzyme was observed. Sodium halides nullified the pH induced global changes in the enzyme, however differential effect of these salts on the active site microenvironment and functional activity of the enzyme was observed.</p> <p>Conclusions</p> <p>The study unequivocally demonstrates that pH induced selective modification of active site microenvironment and not global change in structure or oligomeric status of the enzyme is responsible for the pH dependent change in enzymatic activity of PSAT.</p>http://www.biomedcentral.com/1756-0500/3/52
spellingShingle Bhakuni Vinod
Nozaki Tomoyoshi
Ali Vahab
Mishra Vibhor
<it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship
BMC Research Notes
title <it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship
title_full <it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship
title_fullStr <it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship
title_full_unstemmed <it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship
title_short <it>Entamoeba histolytica </it>Phosphoserine aminotransferase (EhPSAT): insights into the structure-function relationship
title_sort it entamoeba histolytica it phosphoserine aminotransferase ehpsat insights into the structure function relationship
url http://www.biomedcentral.com/1756-0500/3/52
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AT alivahab itentamoebahistolyticaitphosphoserineaminotransferaseehpsatinsightsintothestructurefunctionrelationship
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