Substrate specificity within a family of outer membrane carboxylate channels.
Substrate specificity within a family of outer membrane carboxylate channels.
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外膜羧酸盐通道家族中的底物特异性。
DOI：
10.1371/journal.pbio.1001242
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发表时间：
2012-01
期刊：
影响因子：
9.8
通讯作者：
van den Berg B
中科院分区：
文献类型：
--
作者：
Eren E;Vijayaraghavan J;Liu J;Cheneke BR;Touw DS;Lepore BW;Indic M;Movileanu L;van den Berg B
对革兰氏阴性细菌一大类外膜通道的表征表明，它们如何在营养贫乏的环境中茁壮成长，以及通道失活如何导致抗生素耐药性。许多革兰氏阴性细菌，包括人类病原体，如铜绿假单胞菌，没有大通道孔蛋白。这导致外膜(OM)对小的极性分子高度不渗透，使细菌对许多抗生素产生内在的抗药性。在这样的微生物中，大多数小分子被OprD外膜蛋白家族的成员摄取。在这里，我们表明OprD通道需要底物中的羧基才能有效地运输，在此基础上，我们将OCC家族重新命名为外膜羧酸盐通道。我们进一步表明，根据底物特性的不同，OCC通道可以分为两个亚家族。我们的结果合理地说明了某些细菌如何在营养不良的条件下有效地利用各种底物，而不损害膜的通透性。此外，他们还解释了抗生素引起的渠道失活如何会导致耐药性，但不会导致适应性下降。在感染性疾病的治疗中，新出现的抗生素耐药性是一个日益严重的问题，迫切需要开发新药。在革兰氏阴性细菌中，外膜(OM)阻止小分子的渗透，包括抗生素。OM中存在一系列通道形成蛋白，称为OprD蛋白，能够吸收生长和细胞功能所需的营养物质。由于这些通道也运输抗生素，了解分子是如何被这些蛋白质识别和运输的，应该能够设计出更有效的抗生素。在这里，我们用生物物理和生化方法表征了常见的多重耐药铜绿假单胞菌OprD通道家族的九个成员的结构和底物特异性。因为我们证明了有效地通过这些通道需要底物中存在一个羧基，所以我们将这个通道家族重新命名为外膜羧酸盐通道，或OCC。这种广泛的底物专一性表明，这种有效的运输使细菌能够在营养贫乏的环境中茁壮成长。我们还显示了家族成员之间明显不同的底物特异性，特别是对抗生素，这表明单一通道的突变可以导致抗生素耐药性。这些结果为研究抗生素与OM摄取通道的相互作用提供了框架，这将有助于开发更具渗透性的有效药物。
Characterization of a large family of outer membrane channels from gram-negative bacteria suggest how they can thrive in nutrient-poor environments and how channel inactivation can contribute to antibiotic resistance. Many Gram-negative bacteria, including human pathogens such as Pseudomonas aeruginosa, do not have large-channel porins. This results in an outer membrane (OM) that is highly impermeable to small polar molecules, making the bacteria intrinsically resistant towards many antibiotics. In such microorganisms, the majority of small molecules are taken up by members of the OprD outer membrane protein family. Here we show that OprD channels require a carboxyl group in the substrate for efficient transport, and based on this we have renamed the family Occ, for outer membrane carboxylate channels. We further show that Occ channels can be divided into two subfamilies, based on their very different substrate specificities. Our results rationalize how certain bacteria can efficiently take up a variety of substrates under nutrient-poor conditions without compromising membrane permeability. In addition, they explain how channel inactivation in response to antibiotics can cause resistance but does not lead to decreased fitness. Emerging antibiotic resistance in the treatment of infectious disease is an increasing problem that urgently requires new drug development. In Gram-negative bacteria, the outer membrane (OM) prevents permeation of small molecules, including antibiotics. A family of channel-forming proteins, called OprD proteins, are present in the OM to enable uptake of nutrients required for growth and cellular function. Since these channels also transport antibiotics, understanding how molecules are recognized and transported by these proteins should enable the design of more effective antibiotics. Here, we have characterized by biophysical and biochemical methods the structures and substrate-specificities of nine members of the OprD channel family of a common multidrug-resistant pathogen, Pseudomonas aeruginosa. Because we demonstrate that efficient passage through these channels requires the presence of a carboxyl group in the substrate, we renamed this channel family outer membrane carboxylate channels, or Occ. This broad substrate specificity suggests that such efficient transport allows bacteria to thrive in nutrient-poor environments. We also show markedly varied substrate specificities among the family members, especially for antibiotics, suggesting that mutation of a single channel can result in antibiotic resistance. These results provide the framework for studying the interaction of antibiotics with OM uptake channels, which will facilitate the development of more permeable and thus effective drugs.
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DOI：
10.1073/pnas.77.1.167
发表时间：
1980-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
LUCKEY, M;NIKAIDO, H
通讯作者：
NIKAIDO, H
影响因子：
2.1
作者：
HANCOCK, REW;CAREY, AM
通讯作者：
CAREY, AM
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
16.8
作者：
Biswas, Shyamasri;Mohammad, M. Mohammad;van den Berg, Bert
通讯作者：
van den Berg, Bert
DOI：
10.1073/pnas.1018532108
发表时间：
2011-06-21
影响因子：
11.1
作者：
Lepore, Bryan W.;Indic, Mridhu;van den Berg, Bert
通讯作者：
van den Berg, Bert