S, S-rhizoferrin (enantio-rhizoferrin) - a siderophore of Ralstonia (Pseudomonas) pickettii DSM 6297 - the optical antipode of R, R-rhizoferrin isolated from fungi

From the culture medium of Ralstonia (formerly Burkholderia or Pseudomonas) pickettii DSM 6297 grown under iron-limited conditions an iron complexing compound (siderophore) could be isolated. The structure of the isolated pol ycarboxylate siderophore was determined by spectroscopic methods as S,S-rhi zoferrin, the enantiomer of R,R-rhizoferrin produced by fungi (Zygomycetes) . Transport experiments with radiolabelled iron using S,S- and R,R-rhizofer rin showd no differences in the bacterial Ralstonia strain, while transport of R,R-rhizoferrin was superior in the producing fungal Rhizopus strain, s uggesting stereoselective recognition in the fungus.