1998 Fiscal Year Final Research Report Summary
Studies in membrane topology and function of inner membrane component, MexA,of antibiotic extrusion pump of Pseudomonas aeruginosa
| Project/Area Number |
09670298
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Tokai University |
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Principal Investigator |
YONEYAMA Hiroshi Tokai University, School of Medicine, Assistant Professor, 医学部, 講師 (10220774)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Pseudomonas aeruginosa / multidrug resistance / extrusion pump / inner membrane protein / outer membrane protein / antibiotics |
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| Research Abstract |
Pseudomonas aeruginosa, a main causative agent of opportunistic infections, shows intrinsic and multiantibiotic resistance. The major reason for the antibiotic resistance in this bacterium appeared to be the presence of an energy dependent antibiotic extrusion pump (MexAB-OprM pump) encoded in the mex operon (mexA-mexl3-oprM). To get insight into the mode of antibiotic extrusion by the Mex pump, it is essential to study on the structure and function of each subunit of the pump. Therefore, I analyzed the membrane topology and localization of MexA, a member of membrane fusion protein family, which is thought to link inner membrane pump, MexB, to an outer membrane channel, OprM.I employed the gene fusion technique to analyze the membrane topology of MexA using signal sequenceless beta-lactamase as a reporter and got 78 in-frame MexA-beta--lactamase fusions. All transformants harbored each fusion gene showed ampicillin resistance, indicating that almost all regions of MexA beyond the signal sequence reside in the periplasm. MexA was also found to be modified by lipid(s) at its cysteine residue in the consensus sequence for lipoproteins.
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