Biochemical and immunological properties of lactoferrin binding proteins from Moraxella (Branhamella) catarrhalis

Robert Bonnah, Rong Hua Yu, Henry Wong, Anthony B. Schryvers

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The Neisseriaceae can acquire iron (Fe) from lactoferrin (Lf) using host-Lf receptors on the bacterial surface. The binding proteins that are proposed to constitute the receptor have been identified by isolation with immobilized if. Using CopB-specific monoclonal antibodies and isogenic CopB mutants, we demonstrate that the 84 kDa protein isolated with immobilized human if from Moraxella catarrhalis using low stringency conditions is CopB, an 84 kDa membrane-spanning protein with similarities to other TonB-dependent outer membrane proteins. Affinity isolation of Lf receptors from a variety of M. catarrhalis strains using high stringency conditions revealed a 95 kDa protein migrating slightly faster than LbpA on SDS-PAGE in some strains. Convalescent human antisera from patients infected with M. catarrhalis reacted specifically with this protein, but not LbpA. Proteolysis experiments demonstrated that, unlike LbpA, it was rapidly degraded. The 95 kDa protein, but not LbpA, binds labelled if after SDS-PAGE and electroblotting, suggesting the 95 kDa protein is LbpB, the homologue of TbpB. This protein comigrates with LbpA in most strains, which may explain why it had not been previously identified.

Original languageEnglish (US)
Pages (from-to)89-100
Number of pages12
JournalMicrobial Pathogenesis
Volume24
Issue number2
DOIs
StatePublished - 1998
Externally publishedYes

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Moraxella (Branhamella) catarrhalis
Lactoferrin
Carrier Proteins
Proteins
Neisseriaceae
Polyacrylamide Gel Electrophoresis
Membrane Proteins
Proteolysis
Immune Sera
Iron
Monoclonal Antibodies

Keywords

  • Iron
  • Lactoferrin
  • Lactoferrin binding protein
  • Transferrin
  • Transferrin binding protein

ASJC Scopus subject areas

  • Microbiology
  • Infectious Diseases

Cite this

Biochemical and immunological properties of lactoferrin binding proteins from Moraxella (Branhamella) catarrhalis. / Bonnah, Robert; Yu, Rong Hua; Wong, Henry; Schryvers, Anthony B.

In: Microbial Pathogenesis, Vol. 24, No. 2, 1998, p. 89-100.

Research output: Contribution to journalArticle

Bonnah, Robert ; Yu, Rong Hua ; Wong, Henry ; Schryvers, Anthony B. / Biochemical and immunological properties of lactoferrin binding proteins from Moraxella (Branhamella) catarrhalis. In: Microbial Pathogenesis. 1998 ; Vol. 24, No. 2. pp. 89-100.
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