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| - | [[Image:1jg2.jpg|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1jg2| PDB=1jg2 | SCENE= }} | | {{STRUCTURE_1jg2| PDB=1jg2 | SCENE= }} |
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| - | '''Crystal Structure of L-isoaspartyl (D-aspartyl) O-methyltransferase with adenosine'''
| + | ===Crystal Structure of L-isoaspartyl (D-aspartyl) O-methyltransferase with adenosine=== |
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| - | ==Overview==
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| - | Protein L-isoaspartyl (D-aspartyl) methyltransferases (EC 2.1.1.77) are found in almost all organisms. These enzymes catalyze the S-adenosylmethionine (AdoMet)-dependent methylation of isomerized and racemized aspartyl residues in age-damaged proteins as part of an essential protein repair process. Here, we report crystal structures of the repair methyltransferase at resolutions up to 1.2 A from the hyperthermophilic archaeon Pyrococcus furiosus. Refined structures include binary complexes with the active cofactor AdoMet, its reaction product S-adenosylhomocysteine (AdoHcy), and adenosine. The enzyme places the methyl-donating cofactor in a deep, electrostatically negative pocket that is shielded from solvent. Across the multiple crystal structures visualized, the presence or absence of the methyl group on the cofactor correlates with a significant conformational change in the enzyme in a loop bordering the active site, suggesting a role for motion in catalysis or cofactor exchange. We also report the structure of a ternary complex of the enzyme with adenosine and the methyl-accepting polypeptide substrate VYP(L-isoAsp)HA at 2.1 A. The substrate binds in a narrow active site cleft with three of its residues in an extended conformation, suggesting that damaged proteins may be locally denatured during the repair process in cells. Manual and computer-based docking studies on different isomers help explain how the enzyme uses steric effects to make the critical distinction between normal L-aspartyl and age-damaged L-isoaspartyl and D-aspartyl residues.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_11700066}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 11700066 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_11700066}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Protein repair isomerization]] | | [[Category: Protein repair isomerization]] |
| | [[Category: Rossman methyltransferase]] | | [[Category: Rossman methyltransferase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:10:52 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 20:11:34 2008'' |
Revision as of 17:11, 1 July 2008
Template:STRUCTURE 1jg2
Crystal Structure of L-isoaspartyl (D-aspartyl) O-methyltransferase with adenosine
Template:ABSTRACT PUBMED 11700066
About this Structure
1JG2 is a Single protein structure of sequence from Pyrococcus furiosus. Full crystallographic information is available from OCA.
Reference
Crystal structure of a protein repair methyltransferase from Pyrococcus furiosus with its L-isoaspartyl peptide substrate., Griffith SC, Sawaya MR, Boutz DR, Thapar N, Katz JE, Clarke S, Yeates TO, J Mol Biol. 2001 Nov 9;313(5):1103-16. PMID:11700066
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