Identification of Regions Important for Resistance and Signalling within the Antimicrobial Peptide Transporter BceAB of Bacillus subtilis
Identification of Regions Important for Resistance and Signalling within the Antimicrobial Peptide Transporter BceAB of Bacillus subtilis
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DOI：
10.1128/jb.00419-13
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发表时间：
2013-07-01
影响因子：
3.2
通讯作者：
Gebhard, Susanne
中科院分区：
文献类型：
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作者：
Kallenberg, Felix;Dintner, Sebastian;Gebhard, Susanne
在低G + C含量的革兰氏阳性菌中，对抗菌肽的抗性通常由所谓的抗性模块介导。这些由双组分系统和ATP结合盒转运蛋白组成，其特征在于不寻常的信号转导模式，其中转运蛋白作为抗菌肽的传感器，因为单独的组氨酸激酶不能直接检测底物。因此，转运蛋白实现了双重功能，作为传感器和解毒系统，以赋予抗性，但这些过程的机制细节是未知的。对此的范例和最好理解的例子是枯草芽孢杆菌的BceRS-BceAB模块，其介导对杆菌肽、mersacidin和actagardine的抗性。使用随机诱变的方法，我们在这里表明，突变，影响转运蛋白BceAB的特定功能，主要发现在C-末端区域的通透酶，BceB，特别是在第八跨膜螺旋。此外，我们表明，虽然信号传导和阻力在功能上是相互关联的，可以确定几个突变，强烈影响一个活动的转运，但只有轻微的影响，其他。因此，这两种特性的部分遗传分离可以通过单个氨基酸替换来实现，从而首次深入了解这些不寻常模块的信号传导机制。
In the low-G+C-content Gram-positive bacteria, resistance to antimicrobial peptides is often mediated by so-called resistance modules. These consist of a two-component system and an ATP-binding cassette transporter and are characterized by an unusual mode of signal transduction where the transporter acts as a sensor of antimicrobial peptides, because the histidine kinase alone cannot detect the substrates directly. Thus, the transporters fulfill a dual function as sensors and detoxification systems to confer resistance, but the mechanistic details of these processes are unknown. The paradigm and best-understood example for this is the BceRS-BceAB module of Bacillus subtilis, which mediates resistance to bacitracin, mersacidin, and actagardine. Using a random mutagenesis approach, we here show that mutations that affect specific functions of the transporter BceAB are primarily found in the C-terminal region of the permease, BceB, particularly in the eighth transmembrane helix. Further, we show that while signaling and resistance are functionally interconnected, several mutations could be identified that strongly affected one activity of the transporter but had only minor effects on the other. Thus, a partial genetic separation of the two properties could be achieved by single amino acid replacements, providing first insights into the signaling mechanism of these unusual modules.