title: F199E substitution reduced toxicity of Clostridium perfringens epsilon toxin by depriving the receptor binding capability.
abstract: Epsilon toxin (ETX), a potent toxin, is produced by types B and D strains of Clostridium perfringens, which could cause severe diseases in humans and domestic animals. Mutant rETXF199Ewas previously demonstrated to be a good vaccine candidate. However, the mechanism concerned remains unknown. To clarify how F199E substitution reduced ETX toxicity, we performed a series of experiments. The results showed that the cell-binding and pore-forming ability of rETXF199Ewas almost abolished. We speculated that F199E substitution reduced toxicity by depriving the receptor binding capability of ETX, which contributed to the hypothesis that domain I of ETX is responsible for cell binding. In addition, our data suggested that ETX could cause Ca2+release from intracellular Ca2+stores, which may underlie an alternate pathway leading to cell death. Furthermore, ETX induced crenation of the MDCK cells was observed, with sags and crests first appearing on the surface of condensed MDCK cells, according to scanning electron microscopy. The data also demonstrated the safety and potentiality of rETXF199Eas a vaccine candidate for humans. In summary, findings of this work potentially contribute to a better understanding of the pathogenic mechanism of ETX and the development of vaccine against diseases caused by ETX, using mutant proteins.
authors.affiliation: a Life Science Institute of Hebei Normal University , Shijiazhuang, Hebei Province , PR China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Kang
authors.affiliation: a Life Science Institute of Hebei Normal University , Shijiazhuang, Hebei Province , PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Wenwu
authors.initials: W
authors.lastname: Yao
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Kang
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Hao
authors.initials: H
authors.lastname: Yang
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Ji
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Jiahao
authors.initials: J
authors.lastname: Yao
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Xin
authors.affiliation: a Life Science Institute of Hebei Normal University , Shijiazhuang, Hebei Province , PR China.
authors.forename: Baohua
authors.initials: B
authors.lastname: Zhao
authors.affiliation: b State Key Laboratory of Pathogen and Biosecurity , Institute of Microbiology and Epidemiology , Beijing , PR China.
authors.forename: Jinglin
authors.initials: J
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity*; D004285:Dogs; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity*; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D001427:Bacterial Toxins; C039811:Clostridium perfringens epsilon-toxin; D050505:Mutant Proteins; D011956:Receptors, Cell Surface
keywords: Cell-binding; Clostridium perfringens; Epsilon toxin (ETX); Mutant; Pore-forming; mechanism