| Project/Area Number |
01570230
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | The Institute of Medical Science, The University of Tokyo. |
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Principal Investigator |
TOMITA Toshio The Institute of Medical Science, The University of Tokyo, Research Associate., 医科学研究所, 助手 (00126129)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Staphylococcus aureus / alpha-toxin / membrane damage / liposome / transmembrane channel / membrane fluidity / monoclonal antibody / 毒素六量体形成 |
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| Research Abstract |
Staphylococcal alpha-toxin is a cytolytic 33K-Da polypeptide secreted by pathogenic Staphylococcus aureus. It binds to the membrane of target cells and assembles to hexamer, exhibiting transmembrane-channel activitiy. The toxin is considered to be a prototype for transmembrane-pore-forming proteins including streptolysin O, complement and perforin.
By use of multilamellar liposome composed of Phosphatidyl-Choline (PC) as a model membrane, we studied influence of membrane fluidity on the assembly process of the toxin. Our results indicated that alpha-toxin assembled into hexameric form via a transient, nonhemolytic-monomer form, when PC membrane was fluidized either by the phase transition from gel to liquid crystalline state or by the inclusion of >30 mol % cholesterol in the PC membrane.
To determine the domain of alpha-toxin which is involved in each step of the assembly process, we prepared monoclonal antibodies to the toxin. Monoclonal antibodies obtained from 14 different hybridoma strains were categorized to 3 groups according to their inhibitory action on binding and hemolytic activity of alpha-toxin. Analysis of the epitope which is recognized by each of the monoclonal antibodies is now in progress.
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