Transport and utilization of rhizoferrin bound iron in Mycobacterium smegmatis

Transport and metabolization of iron bound to the fungal siderophore rhizof errin was analyzed by transport kinetics, Mossbauer and EPR spectroscopy. S aturation kinetics (v(max)=24.4 pmol/(mg min), K-m=64.4 mu M) and energy de pendence excluded diffusion and provided evidence for a rhizoferrin transpo rt system in M. smegmatis. Based on the spectroscopic techniques indication s for intracellular presence of the ferric rhizoferrin complex were found. This feature could be of practical importance in the search of novel drugs for the treatment of mycobacterial infections. EPR and Mossbauer spectrosco py revealed different ferritin mineral cores depending on the siderophore i ron source. This finding was interpreted in terms of different protein shel ls, i.e. two types of ferritins.