1kr5
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(New page: 200px<br /> <applet load="1kr5" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kr5, resolution 2.10Å" /> '''Crystal structure o...)
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Revision as of 15:47, 12 November 2007
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Crystal structure of human L-isoaspartyl methyltransferase
Overview
The enzyme l-isoaspartyl methyltransferase initiates the repair of damaged, proteins by recognizing and methylating isomerized and racemized aspartyl, residues in aging proteins. The crystal structure of the human enzyme, containing a bound S-adenosyl-l-homocysteine cofactor is reported here at, a resolution of 2.1 A. A comparison of the human enzyme to homologs from, two other species reveals several significant differences among otherwise, similar structures. In all three structures, we find that three conserved, charged residues are buried in the protein interior near the active site., Electrostatics calculations suggest that these buried charges might make, significant contributions to the energetics of binding the charged, S-adenosyl-l-methionine cofactor and to catalysis. We suggest a possible, structural explanation for the observed differences in reactivity toward, the structurally similar l-isoaspartyl and d-aspartyl residues in the, human, archael, and eubacterial enzymes. Finally, the human structure, reveals that the known genetic polymorphism at residue 119 (Val/Ile) maps, to an exposed region away from the active site.
About this Structure
1KR5 is a Single protein structure of sequence from Homo sapiens with SAH as ligand. Active as Protein-L-isoaspartate(D-aspartate) O-methyltransferase, with EC number 2.1.1.77 Full crystallographic information is available from OCA.
Reference
Crystal structure of human L-isoaspartyl methyltransferase., Ryttersgaard C, Griffith SC, Sawaya MR, MacLaren DC, Clarke S, Yeates TO, J Biol Chem. 2002 Mar 22;277(12):10642-6. Epub 2002 Jan 15. PMID:11792715
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