title: Adhesion properties of a putative polymorphic fimbrial subunit protein from Bifidobacterium longum subsp. longum.
abstract: In our previous study, we found that the open reading frame bl0675 in the genome of Bifidobacterium longum subsp. longum isolated from human feces encoded a novel putative fimbrial protein, was highly polymorphic, and had five variants (A, B, C, D, and E types). The aim of this study was to evaluate the affinity of these variants to porcine colonic mucins (PCMs). Protein-binding properties were examined using the recombinant BL0675 protein containing a C-terminal 6 × His tag (His-BL0675). Surface plasmon resonance analysis demonstrated that the His-BL0675 A type had strong affinity to PCMs (KD = 9.82 × 10(-8) M), whereas the B, C, D, and E types exhibited little or no binding. In a competitive enzyme-linked immunosorbent assay, His-BL0675 A type binding was reduced by addition of mucin oligosaccharides, suggesting that the binding occurs via carbohydrate chains of PCMs. The localization of BL0675 to the B. longum subsp. longum cell surface was confirmed by western blot analysis using A type polyclonal antibodies. Bacterial adhesion of B. longum subsp. longum to PCMs was also blocked by A type-specific antibodies; however, its adhesion properties were strain specific. Our results suggest that the BL0675 variants significantly contribute to the adhesion of B. longum subsp. longum strains. The expression and the adhesive properties of this protein are affected by genetic polymorphisms and are specific for B. longum subsp. longum strains. However, further studies are required on the properties of binding of these putative fimbrial proteins to the human gastrointestinal tract.
authors: Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors: Kenta
authors: K
authors: Suzuki
authors: Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan; Department of Microbiology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, Japan.
authors: Keita
authors: K
authors: Nishiyama
authors: Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors: Hiroki
authors: H
authors: Miyajima
authors: Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors: Ro
authors: R
authors: Osawa
authors: Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors: Yuji
authors: Y
authors: Yamamoto
authors: Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors: Takao
authors: T
authors: Mukai
keywords: Bifidobacterium longum subsp. longum; adhesion; fimbrial subunit protein; mucin; surface plasmon resonance