Functional analysis of the sialic acid-binding adhesin SfaS of pathogenic Escherichia coli by site-specific mutagenesis.
AUTOR(ES)
Morschhäuser, J
RESUMO
The gene coding for the sialic acid-specific adhesin SfaS produced by the S fimbrial adhesin (sfa) determinant of Escherichia coli has been modified by oligonucleotide-directed, site-specific mutagenesis. Lysine 116, arginine 118, and lysine 122 were replaced by threonine, serine, and threonine, respectively. The mutagenized gene clusters were able to produce S fimbrial adhesin complexes consisting of the S-specific subunit proteins including the adhesin SfaS. The mutant clones were further characterized by hemagglutination and by enzyme-linked immunoassay tests with antifimbria- and anti-adhesin-specific monoclonal antibodies, one of which is able to block S-specific binding (Moch et al., Proc. Natl. Acad. Sci. USA 84:3462-3466, 1987). The lysine-122 mutant clone was indistinguishable from the wild-type clone in these assays. Replacement of lysine 116 and arginine 118, however, abolished hemagglutination and resulted in clones which showed a weak (lysine 116) or a negative (arginine 118) reaction with the antiadhesin-specific antibody A1. We therefore suggest that lysine 116 and arginine 118 have an influence on binding of SfaS to the sialic acid residue of the receptor molecule. Substitution of arginine 118 by serine also had a negative effect on the amount of SfaS adhesin proteins isolated from the S fimbrial adhesin complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=258787Documentos Relacionados
- Functional and structural analysis of the sialic acid-binding domain of rotaviruses.
- Functional Analysis of the Streptococcus gordonii DL1 Sialic Acid-Binding Adhesin and Its Essential Role in Bacterial Binding to Platelets
- Analysis of Shiga toxin subunit association by using hybrid A polypeptides and site-specific mutagenesis.
- Agglutination of Streptococcus suis by sialic acid-binding lectins.
- Oligonucleotide-directed double-strand break repair in plasmids of Escherichia coli: a method for site-specific mutagenesis.