Identification of an Essential Region for Translocation of Clostridium difficile Toxin B
| Autor: | Chunli Sun, Huawei Gu, Haiying Wang, Hanping Feng, Shuyi Chen, Jufang Wang, Shan Li |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Virulence Factors Health Toxicology and Mutagenesis Protein domain Bacterial Toxins Clostridium difficile toxin A translocation lcsh:Medicine Clostridium difficile toxin B GTPase Toxicology Article Protein Structure Secondary 03 medical and health sciences conformational change Bacterial Proteins Protein Domains Cell Line Tumor Chlorocebus aethiops Animals endocytosis toxin Vero Cells Enterocolitis Pseudomembranous chemistry.chemical_classification Mice Inbred BALB C biology Clostridioides difficile Protein Stability lcsh:R Clostridium difficile Correction Pseudomembranous colitis Cysteine protease Amino acid Protein Transport 030104 developmental biology Biochemistry chemistry Mutation Proteolysis biology.protein Glucosyltransferase |
| Zdroj: | Toxins, Vol 8, Iss 8, p 241 (2016) Toxins Toxins; Volume 8; Issue 8; Pages: 241 |
| ISSN: | 2072-6651 |
| Popis: | Clostridium difficile toxin A (TcdA) and toxin B (TcdB) are the major virulence factors involved in C. difficile-associated diarrhea and pseudomembranous colitis. TcdA and TcdB both contain at least four distinct domains: the glucosyltransferase domain, cysteine protease domain, receptor binding domain, and translocation domain. Few studies have investigated the translocation domain and its mechanism of action. Recently, it was demonstrated that a segment of 97 amino acids (AA 1756–1852, designated D97) within the translocation domain of TcdB is essential for the in vitro and in vivo toxicity of TcdB. However, the mechanism by which D97 regulates the action of TcdB in host cells and the important amino acids within this region are unknown. In this study, we discovered that a smaller fragment, amino acids 1756–1780, located in the N-terminus of the D97 fragment, is essential for translocation of the effector glucosyltransferase domain into the host cytosol. A sequence of 25AA within D97 is predicted to form an alpha helical structure and is the critical part of D97. The deletion mutant TcdB∆1756–1780 showed similar glucosyltransferase and cysteine protease activity, cellular binding, and pore formation to wild type TcdB, but it failed to induce the glucosylation of Rho GTPase Rac1 of host cells. Moreover, we found that TcdB∆1756–1780 was rapidly degraded in the endosome of target cells, and therefore its intact glucosyltransferase domain was unable to translocate efficiently into host cytosol. Our finding provides an insight into the molecular mechanisms of action of TcdB in the intoxication of host cells. |
| Databáze: | OpenAIRE |
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