Different Biosynthetic Pathways to Fosfomycin in Pseudomonas syringae and Streptomyces Species

Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Antimicrobial Agents and Chemotherapy (Impact Factor: 4.48). 05/2012; 56(8):4175-83. DOI: 10.1128/AAC.06478-11
Source: PubMed


Fosfomycin is a wide-spectrum antibiotic that is used clinically to treat acute cystitis in the United States. The compound is produced by several strains of streptomycetes and pseudomonads. We sequenced the biosynthetic gene cluster responsible for fosfomycin production in Pseudomonas syringae PB-5123. Surprisingly, the biosynthetic pathway in this organism is very different from that in Streptomyces fradiae and Streptomyces wedmorensis. The pathways share the first and last steps, involving conversion of phosphoenolpyruvate to phosphonopyruvate (PnPy) and 2-hydroxypropylphosphonate (2-HPP) to fosfomycin, respectively, but the enzymes converting PnPy to 2-HPP are different. The genome of P. syringae PB-5123 lacks a gene encoding the PnPy decarboxylase found in the Streptomyces strains. Instead, it contains a gene coding for a citrate synthase-like enzyme, Psf2, homologous to the proteins that add an acetyl group to PnPy in the biosynthesis of FR-900098 and phosphinothricin. Heterologous expression and purification of Psf2 followed by activity assays confirmed the proposed activity of Psf2. Furthermore, heterologous production of fosfomycin in Pseudomonas aeruginosa from a fosmid encoding the fosfomycin biosynthetic cluster from P. syringae PB-5123 confirmed that the gene cluster is functional. Therefore, two different pathways have evolved to produce this highly potent antimicrobial agent.

Download full-text


Available from: Bradley S Evans, Mar 18, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Molecular cloning of the biosynthetic gene cluster involved in the production of free 4-chlorothreonine in Streptomyces sp. OH-5093 showed the presence of six open reading frames: thr1, thr2, thr3, orf1, orf2 and thr4. According to bioinformatic analysis thr1, thr2, thr3 and thr4 encode a free-standing adenylation domain, a carrier protein, an Fe(II) nonheme α-ketoglutarate-dependent halogenase and a thioesterase, respectively, indicating the role of these genes in the activation and halogenation of threonine and the release of 4-chlorothreonine in a pathway that closely reflects the formation of this amino acid in the biosynthesis of the lipodepsipeptide syringomycin from Pseudomonas syringae pv. syringae B301DR. Orf1 and orf2 show sequence similarity with alanyl/threonyl-tRNA synthetases editing domains and Drug Metabolite Transporters, respectively. We show that thr3 can replace the halogenase gene syrB2 in the biosynthesis of syringomycin, by functional complementation of the mutant P. s. pv. syringae strain BR135A1 inactivated in syrB2. We also provide an insight into the structure-function relationship of the halogenases Thr3 and SyrB2 using homology modelling and site-directed mutagenesis. © 2012 The Authors Journal compilation © 2012 FEBS.
    FEBS Journal 10/2012; 279(23). DOI:10.1111/febs.12017 · 4.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bacterial infections caused by antibiotic resistant isolates have become a major health problem in recent years since they are very difficult to treat, leading to an increase in morbidity and mortality. Fosfomycin is a broad spectrum bactericidal antibiotic that inhibits cell wall biosynthesis in both Gram negative and Gram positive bacteria. This antibiotic has a unique mechanism of action and inhibits the initial step in peptidoglycan biosynthesis by blocking the enzyme MurA. Fosfomycin has been used successfully for the treatment of urinary tract infections over a long time, but the increased emergence of antibiotic resistance has made fosfomycin a suitable candidate for the treatment of infections caused by multidrug-resistant pathogens, especially in combination with other therapeutic partners. The acquisition of fosfomycin resistance could threaten the reintroduction of this antibiotic for the treatment of bacterial infection. Here we analyse the mechanism of action and molecular mechanisms for the development of fosfomycin resistance, including the modification of the antibiotic target, reduced antibiotic uptake and antibiotic inactivation. In addition, we describe the role of each pathway in clinical isolates.
    06/2013; 2(1). DOI:10.3390/antibiotics20x000x
  • [Show abstract] [Hide abstract]
    ABSTRACT: Natural product biosynthesis has proven a fertile ground for the discovery of novel chemistry. Herein we review the progress made in elucidating the biosynthetic pathways of phosphonate and phosphinate natural products such as the antibacterial compounds dehydrophos and fosfomycin, the herbicidal phosphinothricin-containing peptides, and the antimalarial compound FR-900098. In each case, investigation of the pathway has yielded unusual, and often unprecedented, biochemistry. Likewise, recent investigations have uncovered novel ways to cleave the CP bond to yield phosphate under phosphorus starvation conditions. These include the discovery of novel oxidative cleavage of the CP bond catalyzed by PhnY and PhnZ as well as phosphonohydrolases that liberate phosphate from phosphonoacetate. Perhaps the crown jewel of phosphonate catabolism has been the recent resolution of the longstanding problem of the C-P lyase responsible for reductively cleaving the CP bond of a number of different phosphonates to release phosphate. Taken together, the strides made on both metabolic and catabolic fronts illustrate an array of fascinating biochemistry.
    Current opinion in chemical biology 07/2013; 17(4). DOI:10.1016/j.cbpa.2013.06.018 · 6.81 Impact Factor
Show more