Nucleotide and peptide sequences of the open reading frame encoding a truncated toxin A gene of Clostridium difficile...

The open reading frame encoding a putative truncated toxin A gene of Clostridium difficile in strain CCUG 20309 (ATCC 8864), a strain that produces toxin B but not toxin A, was sequenced by cycle sequencing method. The coding region contains 2097 base pairs and has a GC content of 26.4%. The deduced polypeptide is 50 kDa and is generally hydrophilic. Although strain CCUG 20309 of C. difficile was reported not to produce toxin A, it is enterotoxic, an inherent property of toxin A in pathogenic strains of C. difficile. It therefore remains to be determined whether a truncated form of toxin A could actually be expressed from the open reading frame by this strain of C. difficile.