Sequence analysis of a new open reading frame located in the pathogenicitylocus of Clostridium difficile strain 8864

Strain 8864 is a natural isolate of Clostridium difficile that is toxin B-p ositive and toxin A-negative. Recent work showed that there is a genetic re arrangement occurring at the pathogenicity locus (PaLoc) of the bacteria. O ur investigation in the PaLoc region revealed an open reading frame (tcdf) of 543 bp DNA not reported before. This tcdF could encode a putative polype ptide of 22 kDa. Although no peptide homology was found with other known pr oteins, we postulate that it could be a novel protein because not only high ly consensus ribosome-binding and promoter sequences were found upstream of tcdF, transcript was also identified at the region occupied by tcdF. (C) 1 999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.