1dl5
From Proteopedia
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PROTEIN-L-ISOASPARTATE O-METHYLTRANSFERASE
Overview
BACKGROUND: Formation 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., RESULTS: We have determined the first structure of a PIMT from crystals of, the T. maritima enzyme complexed to S-adenosyl-L-homocysteine (AdoHcy) and, refined it to 1.8 A resolution. Although PIMT forms one structural unit, the protein can be divided functionally into three subdomains. The central, subdomain closely resembles other S-adenosyl-L-methionine-dependent, methyltransferases but bears a striking alteration of topological, connectivity, which is not shared by any other member of this family., Rather than arranged as a mixed beta sheet with topology 6 upward arrow7, downward arrow5 upward arrow4 upward arrow1 upward arrow2 upward arrow3, upward arrow, the central sheet of PIMT is reorganized to 7 upward arrow6, downward arrow5 upward arrow4 upward arrow1 upward arrow2 upward arrow3, upward arrow. AdoHcy is largely buried between the N-terminal and central, subdomains by a conserved and largely hydrophobic loop on one rim of the, binding cleft, and a conserved Ser/Thr-rich beta strand on the other. The, Ser/Thr-rich strand may provide hydrogen bonds for specific interactions, with isoaspartyl substrates. The side chain of Ile-206, a conserved, residue, crosses the cleft, restricting access to the donor methyl group, to a deep well, the putative isoaspartyl methyl acceptor site., CONCLUSIONS: The structure of PIMT reveals a unique modification of the, methyltransferase fold along with a site for specific recognition of, isoaspartyl substrates. The sequence conservation among PIMTs suggests, that the current structure should prove a reliable model for understanding, the repair of isoaspartyl damage in all organisms.
About this Structure
1DL5 is a Single protein structure of sequence from Thermotoga maritima with CD, CL and SAH as ligands. 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 protein isoaspartyl methyltransferase: a catalyst for protein repair., Skinner MM, Puvathingal JM, Walter RL, Friedman AM, Structure. 2000 Nov 15;8(11):1189-201. PMID:11080641
Page seeded by OCA on Tue Nov 20 13:22:52 2007
