During infections the bacteria, Pseudomonas aeruginosa secretes an iron scavenging compound, pyoverdine. Pyoverdine biosynthetic enzymes are proposed to form a complex, the “siderosome”. Pyoverdine consists of a peptide group containing unusual amino acid, formylhydroxyornithine, a chromophore and an acyl side chain. Formyl-hydroxyornithine is synthesized by PvdA and PvdF. PvdA (a monooxygenase), converts ornithine to hydroxy-ornithine, which is highly unstable. PvdF is a formyltransferase which converts hydroxyornithine to formylhydroxyornithine. Formylhydroxyornithine is then incorporated into pyoverdine by a non-ribosomal peptide synthetase. The instability of hydroxyornithine indicates substrate channeling between PvdA and PvdF.
The aim of this research is to investigate the interaction of PvdA and PvdF.
A bacterial two-hybrid system and a co-purification pull down method were used to study the interaction of PvdA and PvdF.
The bacterial two-hybrid system was unable to detect the interaction. However co-purification of PvdF with PvdA showed that PvdF interacts with PvdA.
PvdA and PvdF may have a weaker or transient interaction. The observed interaction between PvdA and PvdF is consistent with their existence as part of the siderosome.