Paquet Maude F, Charette Steve J
Institut de biologie intégrative et des systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada.
Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Quebec, Canada.
Microbiology (Reading). 2025 Apr;171(4). doi: 10.1099/mic.0.001558.
Outer membrane vesicles (OMVs) are naturally produced by Gram-negative bacteria and originate from their outer membrane. They can be extracted using ultracentrifugation or ultrafiltration using concentration columns, followed by purification with a density gradient. However, these methods may co-purify contaminants with similar physical properties. Several studies have identified GroEL, a chaperonin, as a major protein in OMV preparations. Using subsp. as a model, we detected GroEL by mass spectrometry and observed it in transmission electron microscopy images as separate from OMVs. As a cytoplasmic protein complex, GroEL is more likely a contaminant resulting from bacterial lysis during growth rather than an intrinsic OMV component. The model subsp. proved valuable in reaching this conclusion because it produces high levels of extracellular GroEL and low amounts of OMVs. This study emphasizes the need for caution when interpreting the presence of GroEL in OMV preparations and highlights the importance of rigorous purification methods to ensure OMV purity.
外膜囊泡（OMV）由革兰氏阴性菌自然产生，起源于其外膜。可以使用超速离心或使用浓缩柱进行超滤来提取它们，随后通过密度梯度进行纯化。然而，这些方法可能会共纯化具有相似物理性质的污染物。多项研究已确定伴侣蛋白GroEL是OMV制剂中的主要蛋白质。以亚种为模型，我们通过质谱检测到GroEL，并在透射电子显微镜图像中观察到它与OMV是分开的。作为一种细胞质蛋白复合物，GroEL更有可能是生长过程中细菌裂解产生的污染物，而不是OMV的固有成分。亚种模型在得出这一结论方面被证明是有价值的，因为它产生高水平的细胞外GroEL和低量的OMV。这项研究强调在解释OMV制剂中GroEL的存在时需要谨慎，并突出了严格纯化方法对于确保OMV纯度的重要性。
