A nonsense mutation abrogates production of a functional enterotoxin A in Clostridium difficile toxinotype VIII strains of serogroups F and X |
| |
Authors: | Christoph von Eichel-Streiber Ines Zec-Pirnat Miklavz Grabnar Maja Rupnik |
| |
Institution: | Institut für Medizinische Mikrobiologie und Hygiene, Johannes Gutenberg-University, Mainz, Germany. veichel@mail.uni-mainz.de |
| |
Abstract: | Clostridium difficile strains of toxinotype VIII from serogroups F and X are described as toxin B-positive, toxin A-negative (TcdB+ A-), although they harbour almost the entire tcdA gene. To identify the reason for the lack of TcdA detection, we analyzed catalytic and ligand domains of TcdA-1470 of the type strain of serogroup F, strain 1470. Using recombinant fragments, the C-terminal immunodominant ligand domain TcdA3-1470, spanning amino acid residues 1694-2711 (corresponding to VPI 10463 sequence), was detected in Western blots. Similar experiments using the recombinant N-terminal catalytic fragment TcdAc1-2-1470 (amino acid positions 1-544) failed. In addition, this fragment showed no glucosylation activity. We determined the size and the position of alterations in the ligand domain tcdA3-1470 by DNA sequencing. Within the N-terminal fragment tcdAc1-2-1470, a nonsense mutation was identified introducing a stop codon at amino acid position 47. Identical mutations were found in the two serogroup X strains 17663 and 10355. The mutation might explain the lack of TcdA production observed in strains of serotypes F and X. |
| |
Keywords: | Toxin production Polymorphic toxin gene Catalytic domain Ligand domain Toxin A gene Clostridium difficile |
本文献已被 ScienceDirect 等数据库收录! |
|