Pseudomonas aeruginosa D-arabinofuranose biosynthetic pathway and its role in type IV pilus assembly

J Biol Chem. 2011 Aug 12;286(32):28128-37. doi: 10.1074/jbc.M111.255794. Epub 2011 Jun 15.


Pseudomonas aeruginosa strains PA7 and Pa5196 glycosylate their type IVa pilins with α1,5-linked D-arabinofuranose (d-Araf), a rare sugar configuration identical to that found in cell wall polymers of the Corynebacterineae. Despite this chemical identity, the pathway for biosynthesis of α1,5-D-Araf in Gram-negative bacteria is unknown. Bioinformatics analyses pointed to a cluster of seven P. aeruginosa genes, including homologues of the Mycobacterium tuberculosis genes Rv3806c, Rv3790, and Rv3791, required for synthesis of a polyprenyl-linked d-ribose precursor and its epimerization to D-Araf. Pa5196 mutants lacking the orthologues of those genes had non-arabinosylated pilins, poor twitching motility, and significantly fewer surface pili than the wild type even in a retraction-deficient (pilT) background. The Pa5196 pilus system assembled heterologous non-glycosylated pilins efficiently, demonstrating that it does not require post-translationally modified subunits. Together the data suggest that pilins of group IV strains need to be glycosylated for productive subunit-subunit interactions. A recombinant P. aeruginosa PAO1 strain co-expressing the genes for d-Araf biosynthesis, the pilin modification enzyme TfpW, and the acceptor PilA(IV) produced arabinosylated pili, confirming that the Pa5196 genes identified are both necessary and sufficient. A P. aeruginosa epimerase knock-out could be complemented with the corresponding Mycobacterium smegmatis gene, demonstrating conservation between the systems of the Corynebacterineae and Pseudomonas. This work describes a novel Gram-negative pathway for biosynthesis of d-Araf, a key therapeutic target in Corynebacterineae.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabinose / analogs & derivatives*
  • Arabinose / biosynthesis
  • Arabinose / genetics
  • Carbohydrate Epimerases / genetics
  • Carbohydrate Epimerases / metabolism*
  • Fimbriae Proteins / genetics
  • Fimbriae Proteins / metabolism*
  • Fimbriae, Bacterial / genetics
  • Fimbriae, Bacterial / metabolism*
  • Glycosylation
  • Mutation
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / metabolism
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / metabolism*


  • arabinofuranose
  • Fimbriae Proteins
  • Arabinose
  • Carbohydrate Epimerases