Defective mutations within the translocation domain of Clostridium difficile toxin B impair disease pathogenesis.
The Clostridium difficile toxin B is one of the main virulence factors and plays an important role in the pathogenesis of C. difficile infection (CDI). We recently revealed crucial residues in the translocation domain of TcdB for the pore formation and toxin translocation. In this study, we investigated the effects of mutating a critical site involved in pore formation, Leu-1106, to residues that differ in size and polarity (Phe, Ala, Cys, Asp). We observed a broad range of effects on TcdB function in vitro consistent with the role of this site in pore formation and translocation. We show that mice challenged systemically with a lethal dose (LD100) of the most defective mutant (L1106K) showed no symptoms of disease highlighting the importance of this residue and the translocation domain in disease pathogenesis. These findings offer insights into the structure function of the toxin translocation pore, and inform novel therapeutic strategies against CDI.
Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, MD 21201, USA.
Therwa
T
Hamza
Program in Molecular Structure & Function, The Hospital for Sick Children, M5G 0A4, Canada.
Zhifen
Z
Zhang
Program in Molecular Structure & Function, The Hospital for Sick Children, M5G 0A4, Canada Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
Roman A
RA
Melnyk
Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, MD 21201, USA hfeng@umaryland.edu.
Hanping
H
Feng
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D016360:Clostridioides difficile / Q000472:pathogenicity*; D003015:Clostridium Infections / Q000382:microbiology* / Q000473:pathology*; D004252:DNA Mutational Analysis; D004195:Disease Models, Animal; D005260:Female; D051379:Mice; D009154:Mutation; D011041:Poisoning / Q000473:pathology; D052899:Pore Forming Cytotoxic Proteins / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport; D016019:Survival Analysis; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D052899:Pore Forming Cytotoxic Proteins; D037521:Virulence Factors; C031815:toxB protein, Clostridium difficile
Clostridium difficile; TcdB; toxin; translocation domain