title: Characterization of a bovine lactoferrin binding protein of Streptococcus uberis.
abstract: The interaction between Streptococcus uberis and bovine lactoferrin (bLf) has been characterized. The binding of 125I-bLf to S. uberis was time-dependent and displaceable by unlabeled bLf. The Scatchard plot was linear and approximately 7,800 binding sites were expressed by each bacterial cell, with an affinity of 1.0 x 10(-7) M. Both heat and protease treatment of bacterial cells reduced bLf-binding significantly, indicating the presence of a cell surface localized protein receptor for the glycoprotein. One protein was identified from the cell wall of S. uberis as the functionally active bLf-binding protein and it existed in both monomeric and dimeric forms. The recombinant protein expressed in E. coli cells was able to bind bLf and had molecular weights similar to that of native S. uberis. Deletion analysis located the bLf-binding domain to a 200 amino acid region at the amino terminus of Lbp. Analysis of the primary and secondary structure suggested that Lbp is an M-like protein. An isogenic mutant of S. uberis lacking the internal sequence of the lbp gene was constructed by allele replacement. Adherence experiments with wild type S. uberis and the lbp mutant revealed that Lbp is not responsible for attachment of S. uberis to host epithelial cells.
authors.affiliation: Vaccine & Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Sask., Canada S7N 5E3.
authors.forename: Igor
authors.initials: I
authors.lastname: Moshynskyy
authors.forename: Min
authors.initials: M
authors.lastname: Jiang
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fontaine
authors.forename: Jose
authors.initials: J
authors.lastname: Perez-Casal
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Babiuk
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Potter
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015870:Gene Expression; D005798:Genes, Bacterial; D007781:Lactoferrin / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013291:Streptococcus / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D011994:Recombinant Proteins; D037521:Virulence Factors; C027768:lactoferrin binding proteins, bacterial; D007781:Lactoferrin