Probing the barrier function of the outer membrane with chemical conditionality
Probing the barrier function of the outer membrane with chemical conditionality
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DOI：
10.1021/cb600128v
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发表时间：
2006-01-01
影响因子：
4
通讯作者：
Silhavy, Thomas J.
中科院分区：
文献类型：
--
作者：
Ruiz, Natividad;Wu, Tao;Silhavy, Thomas J.
生物膜的一个关键功能是排除有毒的小分子，同时允许营养物质流入。细胞通过控制膜内不同类型蛋白质和脂质的组成来实现这一点，这一过程称为膜生物发生。我们最近提出了一种策略，以确定在革兰氏阴性菌，如大肠杆菌的膜生物合成基因的突变，使外膜（OM）泄漏的抑制剂的选择。我们预测，不同的小分子可以选择不同的抑制因子，因为响应特定选择的突变将根据小分子的结构在不同程度上纠正膜通透性缺陷。我们已经测试了这一假设，通过选择在imp 4213菌株，其中包含一个妥协的OM由于脂多糖生物合成的缺陷，胆汁酸的抗性。我们在这里报告的抑制突变yaeT，它指定了一个必不可少的蛋白质参与β-桶蛋白的组装在OM，赋予阻力的imp 4213菌株中的胆汁酸的特定子集。YaeT是从细菌到人类的保守基因，因为它参与线粒体和叶绿体中的OM生物合成。这些结果表明，结构上不同的有毒小分子选择不同的、高度特异性的遗传解决方案来校正膜渗透性缺陷。imp 4213抑制剂的显著化学特异性为深入了解OM渗透屏障的分子性质提供了依据。
A key function of biological membranes is to exclude toxic small molecules while allowing influx of nutrients. Cells achieve this by controlling the composition of different types of proteins and lipids within the membrane by a process called membrane biogenesis. We have recently proposed a strategy to identify genes involved in membrane biogenesis in Gram-negative bacteria such as Escherichia coli by selecting for suppressors of mutations that render the outer membrane ( OM) leaky. We predicted that different small molecules could select different suppressors because mutations that answer a specific selection will correct the membrane permeability defect to different degrees depending on the structure of the small molecule. We have tested this hypothesis by selecting for resistance to bile acids in an imp4213 strain, which contains a compromised OM owing to a defect in lipopolysaccharide biogenesis. We report here that a suppressor mutation in yaeT, which specifies an essential protein involved in the assembly of beta-barrel proteins in the OM, confers resistance to a specific subset of bile acids in the imp4213 strain. YaeT is conserved from bacteria to man because it is involved in OM biogenesis in mitochondria and chloroplasts. These results demonstrate that structurally different toxic small molecules select different, and highly specific, genetic solutions for correcting membrane- permeability defects. The remarkable chemical specificity of the imp4213 suppressors provides insights into the molecular nature of the OM permeability barrier.