The thiamine kinase (YcfN) enzyme plays a minor but significant role in cobinamide salvaging in Salmonella enterica

J Bacteriol. 2007 Oct;189(20):7310-5. doi: 10.1128/JB.00822-07. Epub 2007 Aug 10.


Cobinamide (Cbi) salvaging is impaired, but not abolished, in a Salmonella enterica strain lacking a functional cobU gene. CobU is a bifunctional enzyme (NTP:adenosylcobinamide [NTP:AdoCbi] kinase, GTP:adenosylcobinamide-phosphate [GTP:AdoCbi-P] guanylyltransferase) whose AdoCbi kinase activity is necessary for Cbi salvaging in this bacterium. Inactivation of the ycfN gene in a DeltacobU strain abrogated Cbi salvaging. Introduction of a plasmid carrying the ycfN(+) allele into a DeltacobU DeltaycfN strain substantially restored Cbi salvaging. Mass spectrometry data indicate that when YcfN-enriched cell extracts were incubated with AdoCbi and ATP, the product of the reaction was AdoCbi-P. Results from bioassays confirmed that YcfN converted AdoCbi to AdoCbi-P in an ATP-dependent manner. YcfN is a good example of enzymes that are used by the cell in multiple pathways to ensure the salvaging of valuable precursors.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Cobamides / metabolism*
  • Cytosol / chemistry
  • Gene Deletion
  • Genetic Complementation Test
  • Mass Spectrometry
  • Mutagenesis, Insertional
  • Organophosphates / metabolism
  • Phosphotransferases (Alcohol Group Acceptor) / chemistry
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / physiology*
  • Salmonella enterica / enzymology*
  • Salmonella enterica / genetics
  • Salmonella enterica / physiology


  • Cobamides
  • Organophosphates
  • adenosylcobinamide phosphate
  • adensoylcobinamide
  • cobinamide
  • Adenosine Triphosphate
  • Phosphotransferases (Alcohol Group Acceptor)
  • thiamin kinase