Characterization of the β-barrel assembly machine accessory lipoproteins from Borrelia burgdorferi.
Characterization of the β-barrel assembly machine accessory lipoproteins from Borrelia burgdorferi.
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DOI：
10.1186/s12866-015-0411-y
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发表时间：
2015-03-24
期刊：
影响因子：
4.2
通讯作者：
Akins DR
中科院分区：
文献类型：
--
作者：
Dunn JP;Kenedy MR;Iqbal H;Akins DR
与迄今为止研究的所有二皮细菌一样，伯氏疏螺旋体也拥有β-桶组装机（BAM）复合体。迄今为止表征的细菌 BAM 复合物由称为 BamA 的必需完整外膜蛋白和一种或多种辅助蛋白组成。辅助蛋白通常是脂质修饰蛋白，通过其脂质部分锚定到外膜的内叶上。我们之前详细鉴定并表征了伯氏疏螺旋体 BamA 蛋白，最近鉴定了由与疏螺旋体 BamA 蛋白相关的开放阅读框 bb0324 和 bb0028 编码的两种脂蛋白。 BAM 辅助脂蛋白在伯氏疏螺旋体中的作用目前尚不清楚。伯氏疏螺旋体 BB0028 的结构模型揭示了独特的 β 螺旋桨折叠，类似于大肠杆菌 BAM 辅助脂蛋白 BamB 的已知结构。此外，BB0324的结构模型与BamD的已知结构高度相似，这与之前的发现一致，即BB0324含有与其他BamD直向同源物相似的四肽重复区域。与 BB0028 和 BB0324 是 BAM 辅助脂蛋白一致，缺乏每种蛋白质表达的突变体被发现表现出改变的膜通透性和对各种抗菌剂的敏感性增强。此外，BB0028突变体还表现出体外生长显着受损。最后，免疫沉淀实验表明，BB0028 和 BB0324 各自与 BamA 特异性且独立地相互作用，在伯氏疏螺旋体中形成 BAM 复合物。结合结构研究、功能测定和免疫共沉淀实验证实，BB0028 和 BB0324 分别是伯氏疏螺旋体中的 BamB 和 BamD 直向同源物，并且对于膜完整性和/或外膜蛋白定位很重要。伯氏疏螺旋体中的 BamB 和 BamD 蛋白均与 BamA 特异性且独立地相互作用，形成三联 BAM 复合物。已经开发了一个工作模型来进一步分析这种致病螺旋体的外膜生物发生和外膜蛋白转运。
Like all diderm bacteria studied to date, Borrelia burgdorferi possesses a β-barrel assembly machine (BAM) complex. The bacterial BAM complexes characterized thus far consist of an essential integral outer membrane protein designated BamA and one or more accessory proteins. The accessory proteins are typically lipid-modified proteins anchored to the inner leaflet of the outer membrane through their lipid moieties. We previously identified and characterized the B. burgdorferi BamA protein in detail and more recently identified two lipoproteins encoded by open reading frames bb0324 and bb0028 that associate with the borrelial BamA protein. The role(s) of the BAM accessory lipoproteins in B. burgdorferi is currently unknown. Structural modeling of B. burgdorferi BB0028 revealed a distinct β-propeller fold similar to the known structure for the E. coli BAM accessory lipoprotein BamB. Additionally, the structural model for BB0324 was highly similar to the known structure of BamD, which is consistent with the prior finding that BB0324 contains tetratricopeptide repeat regions similar to other BamD orthologs. Consistent with BB0028 and BB0324 being BAM accessory lipoproteins, mutants lacking expression of each protein were found to exhibit altered membrane permeability and enhanced sensitivity to various antimicrobials. Additionally, BB0028 mutants also exhibited significantly impaired in vitro growth. Finally, immunoprecipitation experiments revealed that BB0028 and BB0324 each interact specifically and independently with BamA to form the BAM complex in B. burgdorferi. Combined structural studies, functional assays, and co-immunoprecipitation experiments confirmed that BB0028 and BB0324 are the respective BamB and BamD orthologs in B. burgdorferi, and are important in membrane integrity and/or outer membrane protein localization. The borrelial BamB and BamD proteins both interact specifically and independently with BamA to form a tripartite BAM complex in B. burgdorferi. A working model has been developed to further analyze outer membrane biogenesis and outer membrane protein transport in this pathogenic spirochete.
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影响因子：
3.6
作者：
Eggers, CH;Caimano, MJ;Radolf, JD
通讯作者：
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影响因子：
3.7
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Akins, DR
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通讯作者：
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