1992 Fiscal Year Final Research Report Summary
Structure and function relationship of diarrheagenic toxins produced by enteric bacteria
| Project/Area Number |
03454182
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TAKEDA Yoshifumi Faculty of Medicine, Kyoto University, Professor, 医学部, 教授 (30029772)
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| Co-Investigator(Kenkyū-buntansha) |
KURAZONO Hisao Kyoto University, Faculty of Medicine, Assistant, 医学部, 助手 (90186487)
NISHIBUCHI Mitsuaki Faculty of Medicine, Kyoto University, Associate Professor, 医学部, 助教授 (50189304)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Diarrheagenic toxin / Enterohemorrhagic E. coli / Vero toxin / Vibrio parahaemolyticus / Thermostable direct hemolysin / site-directed mutagenesis |
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| Research Abstract |
Structure and function relationship of Vero toxin produced by enterohemorrhagic Escherichia coli and of thermostable direct hemolysin produced by Vibrio parahaemolyticus was studied by using site-directed mutagenesis method.
Vero toxin has an enzymatic activity of RNA N-glycosidase and cleaves a glycosidic bond of adeninosine at 4324th position from 5' terminus of 28S ribosomal RNA of 60S ribosomal subunit in animal cells. Hydrolysis by this enzymatic activity results in the inhibition of EF-1 dependent aminoacyl-tRNA binding to 60S ribosomal subunit, which inhibition of protein synthesis.
The enzymatic as well as biological activity of mutant Vero toxins, such as E167Q (glutamic acid at position 167 from N-terminus is replaced by glutamine), R170L and E167Q-R170L, were significantly decreased indicating that glutamic acid at position 167 and arginine at position 170 are important for the activity of Vero toxin.
Site-directed mutagenesis was also applied to the thermostable direct hemolysin of Vibrio parahaemolyticus Mutant toxins, such as W65H, W65Y, W65L and L66S showed significantly low biological activity indicating that Trp at position 65 from N-terminus and Leu at position 66 were important for the various biological activities.
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