Research Article

Characterizing a Novel L‐Ascorbate Metabolic Pathway in Bacteria

Published: 2020-4

Journal: The FASEB Journal

DOI: 10.1096/fasebj.2020.34.s1.07042

Abstract

L‐Ascorbate, commonly known as Vitamin C, is a naturally abundant carbon source produced in high quantities by plants. The involvement of L‐ascorbate as an antioxidant in processes within the body systems of mammals is well studied, yet L‐ascorbate can also function as a carbon source for some bacterial species.Ralstonia eutrophaH16 (Cupriavidus necatorH16) is a soil bacterium that stores excess carbon in bioplastic granules and catabolizes L‐ascorbate via a previously unknown metabolic pathway. Transcripts for eight genes were upregulated >50‐fold inR. eutrophacells grown with L‐ascorbate compared to fructose or succinate. Three encode homologs of enzymes in L‐lyxonate catabolism to α‐ketoglutarate. Based on annotated functions of the five remaining enzymes, a predicated pathway was hypothesized to generate a‐ketoglutarate from L‐ascorbate. Enzymes not homologous to the L‐lyxonate pathway enzymes were purified and characterizedin vitroby collaborators. MutantR. eutrophastrains were generated, each lacking one of the eight genes, and displayed significant growth defects when grown with L‐ascorbate. Support for a novel pathway for L‐ascorbate catabolism increases our knowledge of related enzyme functions and the involvement of L‐ascorbate in the carbon cycle.

Faculty Members

  • Madison Danielle Jermain - Salisbury University

Themes

  • Gene expression and regulation
  • Metabolic pathways in bacteria
  • L-Ascorbate as a carbon source
  • Enzyme functions in catabolism
  • Ecological implications of carbon cycle

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