In this paper, we report on the chemistry of the rare South African Actinomycete Kribbella speibonae strain SK5, a prolific producer of hydroxamate siderophores and their congeners. Two new analogues, dehydroxylated desferrioxamines, speibonoxamine 1 and desoxy-desferrioxamine D12, have been isolated, together with four known hydroxamates, desferrioxamine D13, desferrioxamine B 4, desoxy-nocardamine 5 and nocardamine 6, and a diketopiperazine (DKP) 7. The structures of 1-7 were characterized by the analysis of HRESIMS and 1D and 2D NMR data, as well as by comparison with the relevant literature. Three new dehydroxy desferrioxamine derivatives 8-10 were tentatively identified in the molecular network of K.speibonae strain SK5 extracts, and structures were proposed based on their MS/MS fragmentation patterns. A plausible spb biosynthetic pathway was proposed. To the best of our knowledge, this is the first report of the isolation of desferrioxamines from the actinobacterial genus Kribbella.
The authors acknowledge funding for this research from the South African Medical Research Council (SAMRC) through the Strategic Health Innovation Partnerships (SHIP) initiative (to D.F.W.), Newton Advanced Fellowship Award (NA160057) (to S.N.S. and M.J.), and the University of Cape Town (to K.S.A.)
- molecular networking
- mass spectrometry
- Molecular networking
- Mass spectrometry