TY  - JOUR
A1  - Schmoll, T.
A1  - Morschhäuser, J.
A1  - Ott, M.
A1  - Ludwig, B.
A1  - Van Die, I.
A1  - Hacker, Jörg
T1  - Complete genetic organization and functional aspects of the Escherichia coli S fimbrial adhesin determinant: nucleotide sequence of the genes sfaB, C, D, E, F.
N2  - The S fimbrial adhesin (sfa) determinant of E. co/i comprises nine genes situated on a stretch of 7.9 kilobases (kb) DNA. Here the nucleotide sequence of the genes sfa B and sfaC situated proximal to the main structural gene sfaA is described. Sfa-LacZ fusions show that the two genes are transcribed in opposite directions. The isolation of mutants in the proximal region of the sfa gene cluster, the construction of sfa-phoA gene fusions and subsequent transcomplementation sturlies indicated that the genes sfaB and sfaC play a role in regulation of the sfa determinant. ln addition the nucleotide sequence of the genes sfa D, sfa E and sfa F situated between the genes sfaA and sfaG responsible for S subunit proteins, were determined. lt is suggested that these genes are involved in transport and assembly of fimbrial subunits. Thus the entire genetic organization of the sfa determinant is presented and compared with the gene clusters coding for P fimbriae (pap), F1 C fimbriae (foc) and type I fimbriae ( fim). The evolutionary relationship of fimbrial adhesin determinants is discussed.
KW  - Infektionsbiologie
KW  - Escherichia coli
KW  - S fimbrial adhesin (Sfa)
KW  - genetic organization
KW  - gene regulation
KW  - nucleotide sequence
Y1  - 1990
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59661
ER  - 
TY  - JOUR
A1  - Morschhäuser, J.
A1  - Hoschützky, H.
A1  - Jann, K.
A1  - Hacker, Jörg
T1  - Functional analysis of the Sialic acid-binding adhesin SfaS of pathogenic Escherichia coli by site-specific mutagenesis
N2  - 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 Iysine 122 were replaced by threonine, serine, and threonine, respectively. The mutagenized gene dusters 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. Sei. USA 84:3462-3466, 1987). The lysine-122 mutantclone was indistinguishable from the wild-type clone in these assays. Replacement of Iysine 116 and ai'ginine 118, however, abolished hemagglutination and resulted in clones which showed a weak (Iysine 116) or a negative (arginine 118) reaction with the antiadhesin-specific antibody Al. We therefore suggest that Iysine 116 and arginine 118 have an inßuence on binding of SfaS to the sialic acid residue of the receptor molecule. Substitution of arginine 118 by serine also had a negative efl"ect on the amount of SfaS adhesin proteins isolated from the S fimbrial adhesin complex.
KW  - Infektionsbiologie
Y1  - 1990
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59613
ER  -