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The role of lysine‐132 and arginine‐136 in the receptor‐binding domain of the K99 fibrillar subunit.
Author(s) -
Jacobs A. A.,
Simons B. H.,
Graaf F. K.
Publication year - 1987
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1987.tb02434.x
Subject(s) - threonine , biology , biochemistry , lysine , serine , arginine , tryptophan , mutant , protein subunit , alanine , site directed mutagenesis , amino acid , escherichia coli , microbiology and biotechnology , phosphorylation , gene
The gene encoding the K99 fibrillar adhesin of Escherichia coli has been modified by oligonucleotide‐directed, site‐specific, mutagenesis. The tryptophan‐67, lysine‐132, lysine‐133 or arginine‐136 were replaced by leucine, threonine, threonine and serine, respectively. The threonine‐133 mutant fibrillae were indistinguishable from wild‐type fibrillae. In contrast, replacement of lysine‐132 or arginine‐136 by threonine or serine, respectively, resulted in mutant fibrillae which had completely lost adhesive capacity, suggesting that the positive charges of these residues are essential for the interaction with the negatively charged sialic acid residue of the receptor molecules. After the replacement of tryptophan‐67 with leucine neither fibrillae nor subunits were detectable, indicating that the mutant product is unstable and that tryptophan‐67 has an essential structural role in the K99 subunit.