Catabolism and detoxification of 1-aminoalkylphosphonic acids: N-acetylation by the phnO gene product

PLoS One. 2012;7(10):e46416. doi: 10.1371/journal.pone.0046416. Epub 2012 Oct 3.

Abstract

In Escherichia coli uptake and catabolism of organophosphonates are governed by the phnCDEFGHIJKLMNOP operon. The phnO cistron is shown to encode aminoalkylphosphonate N-acetyltransferase, which utilizes acetylcoenzyme A as acetyl donor and aminomethylphosphonate, (S)- and (R)-1-aminoethylphosphonate, 2-aminoethyl- and 3-aminopropylphosphonate as acetyl acceptors. Aminomethylphosphonate, (S)-1-aminoethylphosphonate, 2-aminoethyl- and 3-aminopropylphosphonate are used as phosphate source by E. coli phn(+) strains. 2-Aminoethyl- or 3-aminopropylphosphonate but not aminomethylphosphonate or (S)-1-aminoethylphosphonate is used as phosphate source by phnO strains. Neither phn(+) nor phnO strains can use (R)-1-aminoethylphosphonate as phosphate source. Utilization of aminomethylphosphonate or (S)-1-aminoethylphosphonate requires the expression of phnO. In the absence of phnO-expression (S)-1-aminoethylphosphonate is bacteriocidal and rescue of phnO strains requires the simultaneous addition of d-alanine and phosphate. An intermediate of the carbon-phosphorus lyase pathway, 5'-phospho-α-d-ribosyl 1'-(2-N-acetamidoethylphosphonate), a substrate for carbon-phosphorus lyase, was found to accumulate in cultures of a phnP mutant strain. The data show that the physiological role of N-acetylation by phnO-specified aminoalkylphosphonate N-acetyltransferase is to detoxify (S)-1-aminoethylphosphonate, an analog of d-alanine, and to prepare (S)-1-aminoethylphosphonate and aminomethylphosphonate for utilization of the phosphorus-containing moiety.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / metabolism*
  • Magnetic Resonance Spectroscopy
  • Phosphorous Acids / metabolism*

Substances

  • Escherichia coli Proteins
  • PhoP protein, E coli
  • Phosphorous Acids

Grant support

Funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation, and by an Ontario Early Researcher Award (to DLZ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.