| Project/Area Number |
05454195
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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 |
Bacteriology (including Mycology)
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| Research Institution | Tokai University School of Medicine |
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Principal Investigator |
NAKAE Taiji Tokai University School of Medicine, Professor, 医学部, 教授 (50102851)
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| Co-Investigator(Kenkyū-buntansha) |
ISHII Junko Tokai University School of Medicine, Researcher, 医学部, 研究員 (20212813)
YONEYAMA Hiroshi Tokai University School of Medicine.Assistant, 医学部, 助手 (10220774)
YOSHIHARA Eisaku Tokai University School of Medicine.Associate Professor, 医学部, 助教授 (70167063)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1994: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1993: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | Reconstitution / Outer membrane / Pseudomonas aeruginosa / Lipid bilayr / Porin / Antibiotic resistance / Channel / Membrane protein / ポ-リン / Pseudomonas / OprD2 / イミペネム / 脂質平面膜 |
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| Research Abstract |
The outer membrane of Pseudomonas aeruginosa is barrier to the penetration of antibiotics and hence the bacteria is naturally resistant to many antibiotics. Imipenem and closely related carbapenem antibiotics are powerful to the therapy of Pseudomonas aeruginosa infection. The imipenem resistant mutants isolated was found to be lacking the outer membrane protein D2. Hence, it was assumed that protein D2 is responsible in forming the imipenem-permeable channel. Aim of this study is to characterize the specific interaction of imipenem (carbapenem) and the protein D2 porin. To investigate this, a strategy we took was as follows. Planar lipid bilayrs were formed in 0.1 M NaCl solution and to it was added a small amount of highly purified protein D2. We detected the conductivity increment and frequent flickering of about 100 pS in 0.1 M NaCl those are the open/close signal of protein D2 channel. We added 0.7 mM of imipenem to the bath solution and observed that the conductivity was lowered and the channel opening became less frequent. Imipenem at 4 mM completely closed the channel. We tested the effect of another carbapenem, DX8739, and found that this new carbapenem closed the protein D2 channel at about 1 mM.We interpreted these results that imipenem and DX8739 specifically bound to protein D2 and exerted the effect to close the channel. This is the first observation to our best knowledge that the antibiotic and porin channel interaction was determined as single molecular events.
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