4yar
2-Hydroxyethylphosphonate dioxygenase (HEPD) E176H
Structural highlights
FunctionHEPD_STRVT Non-heme-dependent dioxygenase that catalyzes the conversion of 2-hydroxyethylphosphonate (HEP) to hydroxymethylphosphonate (HMP) in the biosynthesis of phosphinothricin tripeptide (PTT). PTT contains the unusual amino acid phosphinothricin attached to 2 alanine residues. Synthetic phosphinothricin (glufosinate) is a key component of commercial herbicides.[1] [2] [3] [4] [5] Publication Abstract from PubMed2-Hydroxyethylphosphonate dioxygenase (HEPD) and methylphosphonate synthase (MPnS) are nonheme iron oxygenases that both catalyze the carbon-carbon bond cleavage of 2-hydroxyethylphosphonate but generate different products. Substrate labeling experiments led to a mechanistic hypothesis in which the fate of a common intermediate determined product identity. We report here the generation of a bifunctional mutant of HEPD (E176H) that exhibits the activity of both HEPD and MPnS. The product distribution of the mutant is sensitive to a substrate isotope effect, consistent with an isotope-sensitive branching mechanism involving a common intermediate. The X-ray structure of the mutant was determined and suggested that the introduced histidine does not coordinate the active site metal, unlike the iron-binding glutamate it replaced. A Common Late-Stage Intermediate in Catalysis by 2-Hydroxyethyl-phosphonate Dioxygenase and Methylphosphonate Synthase.,Peck SC, Chekan JR, Ulrich EC, Nair SK, van der Donk WA J Am Chem Soc. 2015 Feb 26. PMID:25699631[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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