Cloning and expression of a transferrin-binding protein from Actinobacillus pleuropneumoniae.

AUTOR(ES)

Gerlach, G F

RESUMO

An expression library was constructed from Actinobacillus pleuropneumoniae serotype 7. Escherichia coli transformants expressing recombinant proteins were identified by immunoscreening with porcine convalescent serum. One transformant expressing a 60-kDa protein (60K protein) in aggregated form was identified. Serum raised against the recombinant protein recognized a polypeptide with an indistinguishable electrophoretic mobility in the A. pleuropneumoniae wild type after iron-restricted growth only. The recombinant protein bound transferrin after blotting onto nitrocellulose. Using a competitive enzyme-linked immunosorbent assay (ELISA), the specificity of this binding for the amino-terminal half of iron-saturated porcine transferrin was established. Also, the 60K wild-type protein bound hemin as assessed by hemin-agarose chromatography. Hemin could inhibit transferrin binding of the recombinant protein in the competitive ELISA, whereas hemoglobin and synthetic iron chelators failed to do so. Southern blot analysis of several other A. pleuropneumoniae strains indicated that highly homologous sequence is present in eight of eight isolates of serotype 7 and in some isolates of serotypes 2, 3, and 4.

Documentos Relacionados

• Mapping of functional regions on the transferrin-binding protein (TfbA) of Actinobacillus pleuropneumoniae.
• Interference of peptides and specific antibodies with the function of the Actinobacillus pleuropneumoniae transferrin-binding protein.
• Identification of human transferrin-binding sites within meningococcal transferrin-binding protein B.
• Characterization of two genes encoding distinct transferrin-binding proteins in different Actinobacillus pleuropneumoniae isolates.
• Characterization of the diversity and the transferrin-binding domain of gonococcal transferrin-binding protein 2.