Homes for the orphans: utilization of multiple substrate‐binding proteins by ABC transporters
Homes for the orphans: utilization of multiple substrate‐binding proteins by ABC transporters
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DOI：
10.1111/j.1365-2958.2009.06961.x
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发表时间：
2010-01
影响因子：
3.6
通讯作者：
G. Thomas
中科院分区：
文献类型：
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作者：
G. Thomas
从环境中获取营养对所有微生物来说都是必不可少的，而三磷酸腺苷结合盒(ABC)转运蛋白是细菌获得营养的主要途径之一。在本期《分子微生物学》中，Chen等人。描述他们的特征，乍一看似乎是一个简单的ABC转运蛋白，用于获取假单胞菌的季铵化合物(QAC)，但他们在充分确定这一系统的性质的坚持导致了实验证明，QAC吸收利用三个不同的底物结合蛋白(SBPs)，其中两个在基因组上的偏远位置编码为‘孤儿’SBP，每个都能够与一个核心ABC转运蛋白一起发挥作用。基于这个系统的不同寻常的性质，在这个系统中，具有非重叠底物特异性的多个SBPs竞争相同的转运体结合部位，他们设计了优雅的体内实验，表明只有底物结合的SBPs能够与膜域形成功能复合体。这一新发现提供了一条重要的体内数据，有助于进一步深入了解这一无处不在的转运蛋白家族是如何运作的。
Acquiring nutrients from the environment is essential for all microbes, and the ATP‐binding cassette (ABC) transporters are one of the major routes by which bacteria achieve it. In this issue of Molecular Microbiology, Chen et al. describe their characterization of what appeared at first glance a simple ABC transporter for acquisition of quaternary ammonium compounds (QACs) in Pseudomonas sp., but their persistence in fully determining the properties of this system led to the experimental demonstration that QAC uptake utilizes three different substrate‐binding proteins (SBPs), two of which are encoded at remote locations on the genome as ‘orphan’ SBPs that are each able to function with a single core ABC transporter. Building on the unusual nature of this system, in which multiple SBPs with non‐overlapping substrate specificities compete for the same transporter binding site, they designed elegant in vivo experiments that suggest that only substrate‐bound SBPs are able to form functional complexes with the membrane domains. This new finding provides an important piece of in vivo data leading to further insight into how this ubiquitous family of transporters operates.