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Catalytic Site Atlas

CSA LITERATURE entry for 1dl5

E.C. nameprotein-L-isoaspartate(D-aspartate) O-methyltransferase
SpeciesThermotoga maritima (Bacteria)
E.C. Number (IntEnz) 2.1.1.77
CSA Homologues of 1dl5
CSA Entries With UniProtID Q56308
CSA Entries With EC Number 2.1.1.77
PDBe Entry 1dl5
PDBSum Entry 1dl5
MACiE Entry 1dl5

Literature Report

IntroductionFormation of isoaspartyl residues is one of several processes that damage proteins as they age. Protein L-isoaspartate (D-aspartate) O-methyltransferase (PIMT) is a conserved and nearly ubiquitous enzyme that catalyzes the repair of proteins damaged by isoaspartyl formation.
MechansimPIMT catalyzes the transfer of a methyl group from S-adenosyl-L-methionine (SAM) to the alpha-carboxylate side chain of the isoaspartyl residue. Through this transfer, the isoaspartyl group becomes activated for conversion back to the succinimide via a nonenzymatic attack of the nitrogen lone pair of the beta-peptide group on the alpha-carboxylate group. Once back in the succinimide form, hydrolysis can again occur at either carbonyl carbon, converting the protein to the aspartate form or regenerating the isoaspartate. This process cannot restore the amino group to the side chain of an original asparagine, but the pathway can restore the correct configuration to the protein backbone.
Reaction

Catalytic Sites for 1dl5

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
SerA5959macie:sideChainHydrogen bonds to the alpha-carboxylate group promoting the in line attack of O1 on SAM.

Annotated By Reference To The Literature - Site 2 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
SerB5959macie:sideChainHydrogen bonds to the alpha-carboxylate group promoting the in line attack of O1 on SAM.

Literature References

Notes:
Skinner MM
Crystal structure of protein isoaspartyl methyltransferase: a catalyst for protein repair.
Structure 2000 8 1189-1201
PubMed: 11080641
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