A Multitask ATPase Serving Different ABC-Type Sugar Importers in Bacillus subtilis
A Multitask ATPase Serving Different ABC-Type Sugar Importers in Bacillus subtilis
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DOI：
10.1128/jb.00832-10
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发表时间：
2010-10-01
影响因子：
3.2
通讯作者：
de Sa-Nogueira, Isabel
中科院分区：
文献类型：
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作者：
Ferreira, Mario Jose;de Sa-Nogueira, Isabel
枯草芽孢杆菌能够利用从植物生物质中提取的阿拉伯多糖。在这里，通过结合遗传和生理分析，我们确定了AraNPQ导入载体的特征，并鉴定了参与阿拉伯糖摄取的枯草杆菌的初级和次级转运体。我们发现ABC型进口子AraNPQ参与了α-1，5-阿拉伯低聚糖的摄取，至少有四个L-阿拉伯糖基单位。虽然该系统是α-1，5-阿拉伯三糖和α-1，5-阿拉伯四糖的关键转运体，但结果表明，α-1，5-阿拉伯二糖也被二级转运体Arae转运。这种广泛特异性的质子转运体是阿拉伯糖的主要转运体，也负责木糖和半乳糖的摄取。此外，MsmX被证明是激活不完整的AraNPQ导入子的ATPase。此外，结果表明至少存在一个未知的依赖于MsmX的ABC进口体，负责摄取非线性α-1，2-和α-1，3-阿拉伯低聚糖。这项研究将MsmX指定为一种多用途枯草杆菌ATPase，它是为不同的糖转运蛋白提供能量所必需的；阿拉伯低聚糖特异的AraNPQ-MsmX系统；推测的依赖于MsmX的ABC转运蛋白；以及先前鉴定的麦芽糊精特异的MdxEFG-MsmX系统。
Bacillus subtilis is able to utilize arabinopolysaccharides derived from plant biomass. Here, by combining genetic and physiological analyses we characterize the AraNPQ importer and identify primary and secondary transporters of B. subtilis involved in the uptake of arabinosaccharides. We show that the ABC-type importer AraNPQ is involved in the uptake of alpha-1,5-arabinooligosaccharides, at least up to four L-arabinosyl units. Although this system is the key transporter for alpha-1,5-arabinotriose and alpha-1,5-arabinotetraose, the results indicate that alpha-1,5-arabinobiose also is translocated by the secondary transporter AraE. This broad-specificity proton symporter is the major transporter for arabinose and also is accountable for the uptake of xylose and galactose. In addition, MsmX is shown to be the ATPase that energizes the incomplete AraNPQ importer. Furthermore, the results suggest the existence of at least one more unidentified MsmX-dependent ABC importer responsible for the uptake of nonlinear alpha-1,2- and alpha-1,3-arabinooligosaccharides. This study assigns MsmX as a multipurpose B. subtilis ATPase required to energize different saccharide transporters, the arabinooligosaccharide-specific AraNPQ-MsmX system, a putative MsmX-dependent ABC transporter specific for nonlinear arabinooligosaccharides, and the previously characterized maltodextrin-specific MdxEFG-MsmX system.