A mutant hemolysin with lower biological activity produced by a mutant Vibrio parahaemolyticus.
A mutant toxin (m-TDH) of thermostable direct hemolysin (Vp-TDH) of Vibrio parahaemolyticus was isolated from the culture of a strain of this organism mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine. Although the m-TDH had a molecular structure similar to the native Vp-TDH, the m-TDH retained only about 7% residual hemolytic activity of the native toxin. Furthermore, other biological activities of m-TDH, such as lethality in mice and enterotoxicity in rabbit ileal loops, were also weakened. The m-TDH was immunologically indistinguishable from the native Vp-TDH. These results suggest that the m-TDH is only slightly different in structure from the native Vp-TDH. Also, the mutagenized site in m-TDH, which is not immunogenic, seems to be involved in expressing not only hemolytic activity but also lethal and enterotoxic activity.
Honda
T
T
Research Institute for Microbial Diseases, Osaka University, Japan.
Ni
Y X
YX
Hori
S
S
Takakura
H
H
Tsunasawa
S
S
Sakiyama
F
F
Miwatani
T
T
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D006460:Hemolysin Proteins / Q000378:metabolism* / Q000633:toxicity; D007928:Lethal Dose 50; D051379:Mice; D009154:Mutation; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D000596:Amino Acids; D006460:Hemolysin Proteins