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1pym, resolution 1.80Å ()
Ligands: ,
Non-Standard Residues:
Activity: Phosphoenolpyruvate mutase, with EC number
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml


Publication Abstract from PubMed

BACKGROUND: Phosphonate compounds are important secondary metabolites in nature and, when linked to macromolecules in eukaryotes, they might play a role in cell signaling. The first obligatory step in the biosynthesis of phosphonates is the formation of a carbon-phosphorus bond by converting phosphoenolpyruvate (PEP) to phosphonopyruvate (P-pyr), a reaction that is catalyzed by PEP mutase. The PEP mutase functions as a tetramer and requires magnesium ions (Mg2+). RESULTS: The crystal structure of PEP mutase from the mollusk Mytilus edulis, bound to the inhibitor Mg(2+)-oxalate, has been determined using multiwavelength anomalous diffraction, exploiting the selenium absorption edge of a selenomethionine-containing protein. The structure has been refined at 1.8 A resolution. PEP mutase adopts a modified alpha/beta barrel fold, in which the eighth alpha helix projects away from the alpha/beta barrel instead of packing against the beta sheet. A tightly associated dimer is formed, such that the two eighth helices are swapped, each packing against the beta sheet of the neighboring molecule. A dimer of dimers further associates into a tetramer. Mg(2+)-oxalate is buried close to the center of the barrel, at the C-terminal ends of the beta strands. CONCLUSIONS: The tetramer observed in the crystal is likely to be physiologically relevant. Because the Mg(2+)-oxalate is inaccessible to solvent, substrate binding and dissociation might be accompanied by conformational changes. A mechanism involving a phosphoenzyme intermediate is proposed, with Asp58 acting as the nucleophilic entity that accepts and delivers the phosphoryl group. The active-site architecture and the chemistry performed by PEP mutase are different from other alpha/beta-barrel proteins that bind pyruvate or PEP, thus the enzyme might represent a new family of alpha/beta-barrel proteins.

Helix swapping between two alpha/beta barrels: crystal structure of phosphoenolpyruvate mutase with bound Mg(2+)-oxalate., Huang K, Li Z, Jia Y, Dunaway-Mariano D, Herzberg O, Structure. 1999 May;7(5):539-48. PMID:10378273

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

About this Structure

1pym is a 2 chain structure with sequence from Mytilus edulis. Full crystallographic information is available from OCA.


  • Huang K, Li Z, Jia Y, Dunaway-Mariano D, Herzberg O. Helix swapping between two alpha/beta barrels: crystal structure of phosphoenolpyruvate mutase with bound Mg(2+)-oxalate. Structure. 1999 May;7(5):539-48. PMID:10378273

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