biostudies-literatureStack TMMNCRR NIH HHSNational Institute of General Medical SciencesNIGMS NIH HHSSalisbury University1657-1661https://www.ebi.ac.uk/biostudies/studies/S-EPMC7059403biostudies-literatureUnknown142(4)l-Ascorbate (vitamin C) is ubiquitous in both our diet and the environment. Here we report that <i>Ralstonia eutropha</i> H16 (<i>Cupriavidus necator</i> ATCC 17699) uses l-ascorbate as sole carbon source via a novel catabolic pathway. RNaseq identified eight candidate catabolic genes, sequence similarity networks, and genome neighborhood networks guided predictions for function of the encoded proteins, and the predictions were confirmed by <i>in vitro</i> assays and <i>in vivo</i> growth phenotypes of gene deletion mutants. l-Ascorbate, a lactone, is oxidized and ring-opened by enzymes in the cytochrome <i>b</i>₅₆₁ and gluconolactonase families, respectively, to form 2,3-diketo-l-gulonate. A protein predicted to have a WD40-like fold catalyzes an unprecedented benzilic acid reaJournal of the American Chemical SocietyCharacterization of an l-Ascorbate Catabolic Pathway with Unprecedented Enzymatic Transformations.PMC7059403S10 RR028833P01GM118303P01 GM118303Dettmer TMKim CJermain MMorrison KNGerlt JAStack TMMJoyce RWille BBhatti KFrancisco BSNaing YTCarter MSfalseCharacterization of an l-Ascorbate Catabolic Pathway with Unprecedented Enzymatic Transformations.l-Ascorbate (vitamin C) is ubiquitous in both our diet and the environment. Here we report that <i>Ralstonia eutropha</i> H16 (<i>Cupriavidus necator</i> ATCC 17699) uses l-ascorbate as sole carbon source via a novel catabolic pathway. RNaseq identified eight candidate catabolic genes, sequence similarity networks, and genome neighborhood networks guided predictions for function of the encoded proteins, and the predictions were confirmed by <i>in vitro</i> assays and <i>in vivo</i> growth phenotypes of gene deletion mutants. l-Ascorbate, a lactone, is oxidized and ring-opened by enzymes in the cytochrome <i>b</i>₅₆₁ and gluconolactonase families, respectively, to form 2,3-diketo-l-gulonate. A protein predicted to have a WD40-like fold catalyzes an unprecedented benzilic acid rea2020-01-01T00:00:00Z2020 Jan2026-04-18T19:13:26.52Z2021-02-21T04:12:03ZS-EPMC70594033191755810.1021/jacs.9b09863