title: Anchor peptide of transferrin-binding protein B is required for interaction with transferrin-binding protein A.
abstract: Gram-negative bacterial pathogens belonging to the Pasteurellaceae, Moraxellaceae, and Neisseriaceae families rely on an iron acquisition system that acquires iron directly from host transferrin (Tf). The process is mediated by a surface receptor composed of transferrin-binding proteins A and B (TbpA and TbpB). TbpA is an integral outer membrane protein that functions as a gated channel for the passage of iron into the periplasm. TbpB is a surface-exposed lipoprotein that facilitates the iron uptake process. In this study, we demonstrate that the region encompassing amino acids 7-40 of Actinobacillus pleuropneumoniae TbpB is required for forming a complex with TbpA and that the formation of the complex requires the presence of porcine Tf. These results are consistent with a model in which TbpB is responsible for the initial capture of iron-loaded Tf and subsequently interacts with TbpA through the anchor peptide. We propose that TonB binding to TbpA initiates the formation of the TbpB-TbpA complex and transfer of Tf to TbpA.
authors: Department of Microbiology and Infectious Diseases, University of Calgary, Calgary T2N 4N1 Alberta, Canada.
authors: Xue
authors: X
authors: Yang
authors: Rong-hua
authors: RH
authors: Yu
authors: Charles
authors: C
authors: Calmettes
authors: Trevor F
authors: TF
authors: Moraes
authors: Anthony B
authors: AB
authors: Schryvers
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D013552:Swine; D014168:Transferrin / Q000235:genetics / Q000378:metabolism*; D033881:Transferrin-Binding Protein A / Q000235:genetics / Q000378:metabolism*; D033882:Transferrin-Binding Protein B / Q000235:genetics / Q000378:metabolism*
chemical_list: D010455:Peptides; D014168:Transferrin; D033881:Transferrin-Binding Protein A; D033882:Transferrin-Binding Protein B