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==Crystal Structure of 45 amino acid deleted from N-terminal of Phosphoserine Aminotransferase (PSAT) of Entamoeba histolytica== | ==Crystal Structure of 45 amino acid deleted from N-terminal of Phosphoserine Aminotransferase (PSAT) of Entamoeba histolytica== | ||
<StructureSection load='5yii' size='340' side='right' caption='[[5yii]], [[Resolution|resolution]] 1.80Å' scene=''> | <StructureSection load='5yii' size='340' side='right'caption='[[5yii]], [[Resolution|resolution]] 1.80Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[5yii]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5YII OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5YII FirstGlance]. <br> | <table><tr><td colspan='2'>[[5yii]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Enthi Enthi]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5YII OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5YII FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SCN:THIOCYANATE+ION'>SCN</scene></td></tr> | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SCN:THIOCYANATE+ION'>SCN</scene></td></tr> | ||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">EhPSAT, EHI_026360 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=5759 ENTHI])</td></tr> | |||
<tr id='activity'><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 id='activity'><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 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=5yii FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5yii OCA], [http://pdbe.org/5yii PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5yii RCSB], [http://www.ebi.ac.uk/pdbsum/5yii PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5yii 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=5yii FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5yii OCA], [http://pdbe.org/5yii PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5yii RCSB], [http://www.ebi.ac.uk/pdbsum/5yii PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5yii ProSAT]</span></td></tr> | ||
</table> | </table> | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Phosphoserine aminotransferase (PSAT) is a pyridoxal-5'phosphate (PLP)-dependent enzyme that catalyzes the second reversible step in the phosphoserine biosynthetic pathway producing serine. The crystal structure of E. histolytica PSAT (EhPSAT) complexed with PLP was elucidated at 3.0A resolution and the structures of its mutants, EhPSAT_Delta45 and EhPSAT_Delta4, at 1.8 and 2.4A resolution respectively. Deletion of 45 N-terminal residues (EhPSAT_Delta45) resulted in an inactive protein, the structure showed a dimeric arrangement drastically different from that of the wild-type protein, with the two monomers translated and rotated by almost 180 degrees with respect to each other; causing a rearrangement of the active site to which PLP was unable to bind. Deletion of first N-terminal 15 (EhPSAT_Delta15) and four 11th to 14th residues (EhPSAT_Delta4) yielded up to 98% and 90% decrease in the activity respectively. Absence of aldimine linkage between PLP-Lys in the crystal structure of EhPSAT_Delta4 mutant explains for such decrease in activity and describes the importance of these N-terminal residues. Furthermore, a halide-binding site was found in close proximity to the active site. A stretch of six amino acids (146-NNTIYG-151) only conserved in the Entamoeba genus, contributes to halide binding may explain that the halide inhibition could be specific to Entamoeba. | |||
N-terminal residues are crucial for quaternary structure and active site conformation for the phosphoserine aminotransferase from enteric human parasite E. histolytica.,Singh RK, Tomar P, Dharavath S, Kumar S, Gourinath S Int J Biol Macromol. 2019 Jul 1;132:1012-1023. doi:, 10.1016/j.ijbiomac.2019.04.027. Epub 2019 Apr 5. PMID:30959130<ref>PMID:30959130</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 5yii" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Enthi]] | |||
[[Category: Large Structures]] | |||
[[Category: Phosphoserine transaminase]] | [[Category: Phosphoserine transaminase]] | ||
[[Category: Gourinath, S]] | [[Category: Gourinath, S]] | ||
Revision as of 09:15, 10 July 2019
Crystal Structure of 45 amino acid deleted from N-terminal of Phosphoserine Aminotransferase (PSAT) of Entamoeba histolyticaCrystal Structure of 45 amino acid deleted from N-terminal of Phosphoserine Aminotransferase (PSAT) of Entamoeba histolytica
Structural highlights
Publication Abstract from PubMedPhosphoserine aminotransferase (PSAT) is a pyridoxal-5'phosphate (PLP)-dependent enzyme that catalyzes the second reversible step in the phosphoserine biosynthetic pathway producing serine. The crystal structure of E. histolytica PSAT (EhPSAT) complexed with PLP was elucidated at 3.0A resolution and the structures of its mutants, EhPSAT_Delta45 and EhPSAT_Delta4, at 1.8 and 2.4A resolution respectively. Deletion of 45 N-terminal residues (EhPSAT_Delta45) resulted in an inactive protein, the structure showed a dimeric arrangement drastically different from that of the wild-type protein, with the two monomers translated and rotated by almost 180 degrees with respect to each other; causing a rearrangement of the active site to which PLP was unable to bind. Deletion of first N-terminal 15 (EhPSAT_Delta15) and four 11th to 14th residues (EhPSAT_Delta4) yielded up to 98% and 90% decrease in the activity respectively. Absence of aldimine linkage between PLP-Lys in the crystal structure of EhPSAT_Delta4 mutant explains for such decrease in activity and describes the importance of these N-terminal residues. Furthermore, a halide-binding site was found in close proximity to the active site. A stretch of six amino acids (146-NNTIYG-151) only conserved in the Entamoeba genus, contributes to halide binding may explain that the halide inhibition could be specific to Entamoeba. N-terminal residues are crucial for quaternary structure and active site conformation for the phosphoserine aminotransferase from enteric human parasite E. histolytica.,Singh RK, Tomar P, Dharavath S, Kumar S, Gourinath S Int J Biol Macromol. 2019 Jul 1;132:1012-1023. doi:, 10.1016/j.ijbiomac.2019.04.027. Epub 2019 Apr 5. PMID:30959130[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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