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| {{STRUCTURE_1pym| PDB=1pym | SCENE= }} | | {{STRUCTURE_1pym| PDB=1pym | SCENE= }} |
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| '''PHOSPHOENOLPYRUVATE MUTASE FROM MOLLUSK IN WITH BOUND MG2-OXALATE'''
| | ===PHOSPHOENOLPYRUVATE MUTASE FROM MOLLUSK IN WITH BOUND MG2-OXALATE=== |
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| ==Overview==
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| 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.
| | The line below this paragraph, {{ABSTRACT_PUBMED_10378273}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 10378273 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_10378273}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Phosphomutase]] | | [[Category: Phosphomutase]] |
| [[Category: Phosphotransferase]] | | [[Category: Phosphotransferase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 05:38:59 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 09:35:02 2008'' |
