Use of the dehydrophos biosynthetic enzymes to prepare antimicrobial analogs of alaphosphin

Despina J. Bougioukou, Chi P. Ting, Spencer C. Peck, Subha Mukherjee, Wilfred A. Van Der Donk

Research output: Contribution to journalArticle

Abstract

The C-terminal domain of the dehydrophos biosynthetic enzyme DhpH (DhpH-C) catalyzes the condensation of Leu-tRNA Leu with (R)-1-aminoethylphosphonate, the aminophosphonate analog of alanine called Ala(P). The product of this reaction, Leu-Ala(P), is a phosphonodipeptide, a class of compounds that have previously been investigated for use as clinical antibiotics. In this study, we show that DhpH-C is highly substrate tolerant and can condense various aminophosphonates (Gly(P), Ser(P), Val(P), 1-amino-propylphosphonate, and phenylglycine(P)) to Leu. Moreover, the enzyme is also tolerant with respect to the amino acid attached to tRNA Leu . Using a mutant of leucyl tRNA synthetase that is deficient in its proofreading ability allowed the preparation of a series of aminoacyl-tRNA Leu derivatives (Ile, Ala, Val, Met, norvaline, and norleucine). DhpH-C accepted these aminoacyl-tRNA derivatives and condensed the amino acid with l-Ala(P) to form the corresponding phosphonodipeptides. A subset of these peptides displayed antimicrobial activities demonstrating that the enzyme is a versatile biocatalyst for the preparation of antimicrobial peptides. We also investigated another enzyme from the dehydrophos biosynthetic pathway, the 2-oxoglutarate dependent enzyme DhpA. This enzyme oxidizes 2-hydroxyethylphosphonate to 1,2-dihydroxyethylphosphonate en route to l-Ala(P), but longer incubation results in overoxidation to 1-oxo-2-hydroxyethylphosphonate. This α-ketophosphonate was converted by the pyridoxal phosphate dependent enzyme DhpD into l-Ser(P). Thus, the dehydrophos biosynthetic enzymes can generate not only l-Ala(P) but also l-Ser(P).

Original languageEnglish (US)
Pages (from-to)822-829
Number of pages8
JournalOrganic and Biomolecular Chemistry
Volume17
Issue number4
DOIs
StatePublished - Jan 1 2019

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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