1r18

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[[Image:1r18.jpg|left|200px]]
[[Image:1r18.jpg|left|200px]]
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{{Structure
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<!--
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|PDB= 1r18 |SIZE=350|CAPTION= <scene name='initialview01'>1r18</scene>, resolution 2.20&Aring;
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The line below this paragraph, containing "STRUCTURE_1r18", creates the "Structure Box" on the page.
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|SITE=
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You may change the PDB parameter (which sets the PDB file loaded into the applet)
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|LIGAND= <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene>
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or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
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|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Protein-L-isoaspartate(D-aspartate)_O-methyltransferase Protein-L-isoaspartate(D-aspartate) O-methyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.77 2.1.1.77] </span>
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or leave the SCENE parameter empty for the default display.
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|GENE= PCMT ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=7227 Drosophila melanogaster])
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-->
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|DOMAIN=
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{{STRUCTURE_1r18| PDB=1r18 | SCENE= }}
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|RELATEDENTRY=[[1i1n|1I1N]], [[1jg1|1JG1]], [[1jg3|1JG3]], [[1dl5|1DL5]]
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|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1r18 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1r18 OCA], [http://www.ebi.ac.uk/pdbsum/1r18 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1r18 RCSB]</span>
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}}
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'''Drosophila protein isoaspartyl methyltransferase with S-adenosyl-L-homocysteine'''
'''Drosophila protein isoaspartyl methyltransferase with S-adenosyl-L-homocysteine'''
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Catalytic implications from the Drosophila protein L-isoaspartyl methyltransferase structure and site-directed mutagenesis., Bennett EJ, Bjerregaard J, Knapp JE, Chavous DA, Friedman AM, Royer WE Jr, O'Connor CM, Biochemistry. 2003 Nov 11;42(44):12844-53. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/14596598 14596598]
Catalytic implications from the Drosophila protein L-isoaspartyl methyltransferase structure and site-directed mutagenesis., Bennett EJ, Bjerregaard J, Knapp JE, Chavous DA, Friedman AM, Royer WE Jr, O'Connor CM, Biochemistry. 2003 Nov 11;42(44):12844-53. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/14596598 14596598]
[[Category: Drosophila melanogaster]]
[[Category: Drosophila melanogaster]]
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[[Category: Protein-L-isoaspartate(D-aspartate) O-methyltransferase]]
 
[[Category: Single protein]]
[[Category: Single protein]]
[[Category: Bennett, E J.]]
[[Category: Bennett, E J.]]
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[[Category: Jr., W E.Royer.]]
[[Category: Jr., W E.Royer.]]
[[Category: Knapp, J E.]]
[[Category: Knapp, J E.]]
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[[Category: isomerization]]
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[[Category: Isomerization]]
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[[Category: methyltransferase]]
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[[Category: Methyltransferase]]
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[[Category: protein repair]]
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[[Category: Protein repair]]
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[[Category: s-adenosyl homocysteine]]
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[[Category: S-adenosyl homocysteine]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:57:02 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:21:47 2008''
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Revision as of 03:57, 3 May 2008

Template:STRUCTURE 1r18

Drosophila protein isoaspartyl methyltransferase with S-adenosyl-L-homocysteine


Overview

Protein L-isoaspartyl methyltransferases (PIMT; EC 2.1.1.77) catalyze the S-adenosylmethionine-dependent methylation of L-isoaspartyl residues that arise spontaneously in proteins with age, thereby initiating a repair process that restores the normal backbone configuration to the damaged polypeptide. In Drosophila melanogaster, overexpression of PIMT in transgenic flies extends the normal life span, suggesting that protein damage can be a limiting factor in longevity. To understand structural features of the Drosophila PIMT (dPIMT) important for catalysis, the crystal structure of dPIMT was determined at a resolution of 2.2 A, and site-directed mutagenesis was used to identify the role of Ser-60 in catalysis. The core structure of dPIMT is similar to the modified nucleotide-binding fold observed in PIMTs from extreme thermophiles and humans. A striking difference of the dPIMT structure is the rotation of the C-terminal residues by 90 degrees relative to the homologous structures. Effectively, this displacement generates a more open conformation that allows greater solvent access to S-adenosylhomocysteine, which is almost completely buried in other PIMT structures. The enzyme may alternate between the open conformation found for dPIMT and the more closed conformations described for other PIMTs during its catalytic cycle, thereby allowing the exchange of substrates and products. Catalysis by dPIMT requires the side chain of the conserved, active site residue Ser-60, since substitution of this residue with Thr, Gln, or Ala reduces or abolishes the methylation of both protein and isoaspartyl peptide substrates.

About this Structure

1R18 is a Single protein structure of sequence from Drosophila melanogaster. Full crystallographic information is available from OCA.

Reference

Catalytic implications from the Drosophila protein L-isoaspartyl methyltransferase structure and site-directed mutagenesis., Bennett EJ, Bjerregaard J, Knapp JE, Chavous DA, Friedman AM, Royer WE Jr, O'Connor CM, Biochemistry. 2003 Nov 11;42(44):12844-53. PMID:14596598 Page seeded by OCA on Sat May 3 06:57:02 2008

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