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Discrimination between apo and iron-loaded forms of transferrin by transferrin binding protein B and its N-terminal subfragment.
- Source :
-
Microbial pathogenesis [Microb Pathog] 1998 Oct; Vol. 25 (4), pp. 175-80. - Publication Year :
- 1998
-
Abstract
- Many pathogens of the Pasteurellaceae and Neisseriaceae possess a surface receptor that binds transferrin (Tf) as an initial step in an iron acquisition process. This receptor is comprised of two proteins, transferrin binding protein A (TbpA) and transferrin binding protein B (TbpB). Since the ability to recognize the iron-loaded form of Tf preferentially would be a useful attribute of these receptors, we examined this property in a number of bacterial species. In solid-phase binding assays with isolated membranes, only the receptor from Moraxella catarrhalis was capable of preferentially binding iron-loaded Tf. In a competitive affinity isolation assay which enabled us to resolve TbpA and TbpB, TbpA from all tested species was shown to bind both apo and iron-loaded Tf. Under these assay conditions TbpB from M. catarrhalis, Haemophilus somnus and Pasteurella haemolytica discriminated between apo and holo Tf, whereas TbpB from Neisseria meningitidis showed no discrimination. The ability of TbpB from N. meningitidis to bind iron-saturated hTf preferentially became evident in a TbpA- background or by using recombinant TbpB. In binding assays with recombinant fusion proteins, both intact TbpB and the N-terminal half of TbpB from all the tested species preferentially bound Fe-loaded Tf, indicating that this may be a conserved mechanism by which these organisms optimize their ability to acquire iron.<br /> (Copyright 1998 Academic Press.)
- Subjects :
- Animals
Bacterial Outer Membrane Proteins isolation & purification
Cattle
Cloning, Molecular
Electrophoresis, Polyacrylamide Gel
Haemophilus chemistry
Humans
Mannheimia haemolytica chemistry
Moraxella catarrhalis chemistry
Receptors, Transferrin genetics
Recombinant Proteins metabolism
Bacterial Outer Membrane Proteins metabolism
Iron metabolism
Receptors, Transferrin metabolism
Transferrin metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0882-4010
- Volume :
- 25
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Microbial pathogenesis
- Publication Type :
- Academic Journal
- Accession number :
- 9817820
- Full Text :
- https://doi.org/10.1006/mpat.1998.0226