A Common Late-Stage Intermediate in Catalysis by 2-Hydroxyethyl-phosphonate Dioxygenase and Methylphosphonate Synthase.Peck, S.C., Chekan, J.R., Ulrich, E.C., Nair, S.K., van der Donk, W.A.
(2015) J Am Chem Soc 137: 3217-3220
- PubMed: 25699631
- DOI: https://doi.org/10.1021/jacs.5b00282
- Primary Citation of Related Structures:
- PubMed Abstract:
2-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.
Howard Hughes Medical Institute and Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.