Veith Paul D, Chen Yu-Yen, Chen Dina, O'Brien-Simpson Neil M, Cecil Jessica D, Holden James A, Lenzo Jason C, Reynolds Eric C
Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne , 720 Swanston Street, Melbourne, Victoria 3010, Australia.
J Proteome Res. 2015 Dec 4;14(12):5355-66. doi: 10.1021/acs.jproteome.5b00878. Epub 2015 Nov 5.
Tannerella forsythia, a Gram-negative oral bacterium closely associated with chronic periodontitis, naturally produces outer membrane vesicles (OMVs). In this study, OMVs were purified by gradient centrifugation, and the proteome was investigated together with cellular fractions using LC-MS/MS analyses of SDS-PAGE fractions, resulting in the identification of 872 proteins including 297 OMV proteins. Comparison of the OMV proteome with the subcellular proteomes led to the localization of 173 proteins to the vesicle membrane and 61 proteins to the vesicle lumen, while 27 substrates of the type IX secretion system were assigned to the vesicle surface. These substrates were generally enriched in OMVs; however, the stoichiometry of the S-layer proteins, TfsA and TfsB, was significantly altered, potentially to accommodate the higher curvature required of the S-layer around OMVs. A vast number of TonB-dependent receptors related to SusC, together with their associated SusD-like lipoproteins, were identified, and these were also relatively enriched in OMVs. In contrast, other lipoproteins were significantly depleted from the OMVs. This study identified the highest number of membrane-associated OMV proteins to date in any bacterium and conclusively demonstrates cargo sorting of particular classes of proteins, which may have significant impact on the virulence of OMVs.
福赛斯坦纳菌是一种与慢性牙周炎密切相关的革兰氏阴性口腔细菌，能自然产生外膜囊泡（OMV）。在本研究中，通过梯度离心法纯化OMV，并使用SDS-PAGE组分的LC-MS/MS分析对蛋白质组以及细胞组分进行研究，共鉴定出872种蛋白质，其中包括297种OMV蛋白质。将OMV蛋白质组与亚细胞蛋白质组进行比较，结果显示有173种蛋白质定位于囊泡膜，61种蛋白质定位于囊泡腔，同时有27种IX型分泌系统的底物定位于囊泡表面。这些底物通常在OMV中富集；然而，表层蛋白TfsA和TfsB的化学计量发生了显著变化，这可能是为了适应围绕OMV的表层所需的更高曲率。鉴定出大量与SusC相关的依赖TonB的受体及其相关的类似SusD的脂蛋白，它们在OMV中也相对富集。相比之下，其他脂蛋白在OMV中显著减少。本研究确定了迄今为止在任何细菌中数量最多的与膜相关的OMV蛋白质，并最终证明了特定类别的蛋白质的货物分选，这可能对OMV的毒力产生重大影响。
