Studies in membrane topology and function of inner membrane component, MexA,of antibiotic extrusion pump of Pseudomonas aeruginosa

铜绿假单胞菌抗生素挤出泵膜拓扑结构及内膜成分MexA功能研究

• 批准号: 09670298
• 负责人: YONEYAMA Hiroshi
• 金额: $ 1.66万
• 依托单位: Tokai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09670298/
• 关键词: Pseudomonas aeruginosa; multidrug resistance; extrusion pump; inner membrane protein; outer membrane protein; antibiotics; 他剤耐性; Pseudomonas aeruginosa; multidrug resistance; extrusion pump; inner membrane protein; outer membrane protein; antibiotics; 他剤耐性

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.

铜绿假单胞菌是机会性感染的主要病因，表现出内在的和多动生源性的耐药性。该细菌中抗生素耐药性的主要原因似乎是在MEX操纵子（MEXA-MEXL3-OPRM）中编码的依赖能量的抗生素挤出泵（MEXAB-OPRM泵）。为了深入了解MEX泵的抗生素挤出方式，必须研究泵的每个亚基的结构和功能。 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融合。所有融合基因的转化子均显示氨苄青霉素的耐药性，表明MEXA的几乎所有信号序列以外的所有区域都驻留在周期中。还发现MEXA在脂蛋白共识序列中通过脂质（S）在其半胱氨酸残基处进行了修饰。