Centre de Recherches sur les Macromolécules Végétales (CERMAV), CNRS, University Grenoble Alpes, 38041 Grenoble, France.
Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, Freiburg Institute of Advanced Studies (FRIAS), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.
Biomolecules. 2023 Feb 9;13(2):335. doi: 10.3390/biom13020335.
The present report assesses the capability of a soluble glycosyltransferase to modify glycolipids organized in two synthetic membrane systems that are attractive models to mimic cell membranes: giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLBs). The objective was to synthesize the Gb3 antigen (Galα1,4Galβ1,4Glcβ-Cer), a cancer biomarker, at the surface of these membrane models. A soluble form of LgtC that adds a galactose residue from UDP-Gal to lactose-containing acceptors was selected. Although less efficient than with lactose, the ability of LgtC to utilize lactosyl-ceramide as an acceptor was demonstrated on GUVs and SLBs. The reaction was monitored using the B-subunit of Shiga toxin as Gb3-binding lectin. Quartz crystal microbalance with dissipation analysis showed that transient binding of LgtC at the membrane surface was sufficient for a productive conversion of LacCer to Gb3. Molecular dynamics simulations provided structural elements to help rationalize experimental data.
本报告评估了一种可溶性糖基转移酶在两种合成膜系统中修饰糖脂的能力，这两种系统是模拟细胞膜的有吸引力的模型：巨大的单层囊泡（GUV）和支持的脂质双层（SLB）。目的是在这些膜模型的表面合成Gb3 抗原（Galα1,4Galβ1,4Glcβ-Cer），这是一种癌症生物标志物。选择了一种从 UDP-Gal 添加一个半乳糖残基到含有乳糖的受体的可溶性 LgtC 形式。尽管效率低于乳糖，但证明 LgtC 能够在 GUV 和 SLB 上利用乳糖神经酰胺作为受体。使用 Shiga 毒素 B 亚基作为 Gb3 结合凝集素监测反应。石英晶体微天平耗散分析表明，LgtC 在膜表面的瞬时结合足以将 LacCer 有效地转化为 Gb3。分子动力学模拟提供了结构元素，有助于合理化实验数据。
