Hydroxamate recognition during iron transport from hydroxamate-ion chelates.
Kinetics of radioactive iron transport from three structurally different secondary hydroxamate-iron chelates (schizokinen-iron, produced by Bacillus megaterium ATCC 19213; Desferal-iron, produced by an actinomycete; and aerobactin-iron, produced by Aerobacter aerogenes 62-1) revealed that B. megaterium SK11 (a mutant which cannot synthesize schizokinen) has a specific transport system for utilization of ferric hydroxamates with a recognition capacity based on the chemical structure of the hydroxamate. Both Desferal and schizokinen enhanced iron uptake in this organism; however, Desferal-iron delivered only one-sixth the level of iron incorporated from the schizokinen-iron chelate. Desferal-iron did not generate the rapid rates of iron transport noted with schizokinen-iron at elevated iron concentrations. Assays containing large excesses of either iron-free Desferal or iron-free schizokinen suggested that the iron-free hydroxamate may compete with the ferric hydroxamate for acceptance by the transport system although the system has greater affinity for the iron chelate. Aerobactin-iron did not stimulate iron uptake in B. megaterium SK11 and aerobactin inhibited growth of this organism, indicating that B. megaterium SK11 cannot efficiently process the aerobactin-iron chelate.
D001410:Bacillus megaterium / Q000254:growth & development / Q000378:metabolism*; D001693:Biological Transport, Active; D055598:Chemical Phenomena; D002621:Chemistry; D004579:Electron Transport; D004754:Enterobacter / Q000378:metabolism; D006877:Hydroxamic Acids / Q000096:biosynthesis / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000096:biosynthesis / Q000378:metabolism*; D007503:Iron Isotopes; D009154:Mutation; D013302:Streptomyces / Q000378:metabolism
D006877:Hydroxamic Acids; D007502:Iron Chelating Agents; D007503:Iron Isotopes; D007501:Iron