title: Cloning of Clostridium difficile toxin B gene and demonstration of high N-terminal homology between toxin A and B.
abstract: High titered Clostridium sordellii lethal toxin antiserum, cross-reactive with C. difficile cytotoxin B (ToxB), was used to isolate toxB fragments from a C. difficile expression library. Recombinant clones containing toxB fragments of the 5' and 3' end were isolate. A 2.5-kb HincII fragment of chromosomal DNA overlaps both groups of clones. A partial restriction map of the total toxB gene is presented. The gene is positioned upstream of utxA and toxA, toxB has a size of 6.9 kb, corresponding to a 250-kDa polypeptide. A partial sequence of the 5' end of toxB was determined. The sequence contains 398 bp upstream of toxB with a putative Shine-Dalgarno box (AGGAGA) and 609 bp of the toxB open reading frame. The N-terminal 203 amino acids of ToxB were compared with the N-terminal amino acids of the enterotoxin A (ToxA). A homology of 64% of the residues was detected, which proves the relatedness of ToxA and ToxB of C. difficile.
authors.affiliation: Institut für Medizinische Mikrobiologie, Johannes-Gutenberg-Universität, Mainz, Federal Republic of Germany.
authors.forename: C
authors.initials: C
authors.lastname: von Eichel-Streiber
authors.forename: R
authors.initials: R
authors.lastname: Laufenberg-Feldmann
authors.forename: S
authors.initials: S
authors.lastname: Sartingen
authors.forename: J
authors.initials: J
authors.lastname: Schulze
authors.forename: M
authors.initials: M
authors.lastname: Sauerborn
mesh_terms: D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D016360:Clostridioides difficile / Q000235:genetics* / Q000276:immunology; D003429:Cross Reactions; D015342:DNA Probes; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015342:DNA Probes; D004269:DNA, Bacterial; C031815:toxB protein, Clostridium difficile