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A common late-stage intermediate in catalysis by 2-hydroxyethyl-phosphonate dioxygenase and methylphosphonate synthase.

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.

SUBMITTER: Peck SC

PROVIDER: S-EPMC4487810 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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A common late-stage intermediate in catalysis by 2-hydroxyethyl-phosphonate dioxygenase and methylphosphonate synthase.

Peck Spencer C SC Chekan Jonathan R JR Ulrich Emily C EC Nair Satish K SK van der Donk Wilfred A WA

Journal of the American Chemical Society 20150226 9

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 distribu ...[more]

PMID: 25699631

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