Iron piracy: acquisition of transferrin-bound iron by bacterial pathogens.
The mechanism of iron utilization from transferrin has been most extensively characterized in the pathogenic Neisseria species and Haemophilus species. Two transferrin-binding proteins, Tbp1 and Tbp2, have been identified in these pathogens and are thought to be components of the transferrin receptor. Tbp1 appears to be an integral, TonB-dependent outer membrane protein while Tbp2, a lipoprotein, may be peripherally associated with the outer membrane. The relative contribution of each of these proteins to transferrin binding and utilization is discussed and a model of iron uptake from transferrin is presented. Sequence comparisons of the genes encoding neisserial transferrin-binding proteins suggest that they are probably under positive selection for variation and may have resulted from inter-species genetic exchange.
Cornelissen
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Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill 27599.
Sparling
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D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007501:Iron / Q000378:metabolism*; D033862:Iron-Binding Proteins; D008954:Models, Biological; D009343:Neisseria / Q000235:genetics / Q000378:metabolism; D011990:Receptors, Transferrin / Q000235:genetics / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism*; D033863:Transferrin-Binding Proteins
D002352:Carrier Proteins; D033862:Iron-Binding Proteins; D011990:Receptors, Transferrin; D014168:Transferrin; D033863:Transferrin-Binding Proteins; D007501:Iron