Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark.
Glycoconj J. 2012 Jan;29(1):1-12. doi: 10.1007/s10719-011-9359-9. Epub 2011 Nov 22.
Glycosphingolipids (GSLs) are well known ubiquitous constituents of all eukaryotic cell membranes, yet their normal biological functions are not fully understood. As with other glycoconjugates and saccharides, solid phase display on microarrays potentially provides an effective platform for in vitro study of their functional interactions. However, with few exceptions, the most widely used microarray platforms display only the glycan moiety of GSLs, which not only ignores potential modulating effects of the lipid aglycone, but inherently limits the scope of application, excluding, for example, the major classes of plant and fungal GSLs. In this work, a prototype "universal" GSL-based covalent microarray has been designed, and preliminary evaluation of its potential utility in assaying protein-GSL binding interactions investigated. An essential step in development involved the enzymatic release of the fatty acyl moiety of the ceramide aglycone of selected mammalian GSLs with sphingolipid N-deacylase (SCDase). Derivatization of the free amino group of a typical lyso-GSL, lyso-G(M1), with a prototype linker assembled from succinimidyl-[(N-maleimidopropionamido)-diethyleneglycol] ester and 2-mercaptoethylamine, was also tested. Underivatized or linker-derivatized lyso-GSL were then immobilized on N-hydroxysuccinimide- or epoxide-activated glass microarray slides and probed with carbohydrate binding proteins of known or partially known specificities (i.e., cholera toxin B-chain; peanut agglutinin, a monoclonal antibody to sulfatide, Sulph 1; and a polyclonal antiserum reactive to asialo-G(M2)). Preliminary evaluation of the method indicated successful immobilization of the GSLs, and selective binding of test probes. The potential utility of this methodology for designing covalent microarrays that incorporate GSLs for serodiagnosis is discussed.
糖脂(GSLs)是真核细胞膜中普遍存在的成分,但其正常的生物学功能尚未完全了解。与其他糖缀合物和糖一样,固相展示在微阵列上为体外研究它们的功能相互作用提供了一个有效的平台。然而,除了少数例外,使用最广泛的微阵列平台仅显示 GSL 的糖部分,这不仅忽略了脂质糖苷配基的潜在调节作用,而且固有地限制了应用范围,例如排除了植物和真菌 GSL 的主要类别。在这项工作中,设计了一种原型“通用”基于 GSL 的共价微阵列,并初步评估了其在测定蛋白-GSL 结合相互作用中的潜在用途。在开发过程中,涉及用鞘脂 N-脱酰酶(SCDase)从选定的哺乳动物 GSL 的神经酰胺糖苷配基中酶促释放脂肪酸酰基部分。还测试了通过琥珀酰亚胺基-[(N-马来酰亚胺丙酰胺基)-二乙二醇]酯和 2-巯基乙胺组装的原型接头将典型的溶神经酰胺 GSL,溶神经酰胺 G(M1)的游离氨基进行衍生化。然后将未衍生或接头衍生的溶神经酰胺 GSL 固定在 N-羟基琥珀酰亚胺或环氧化物激活的玻璃微阵列载玻片上,并与具有已知或部分已知特异性的碳水化合物结合蛋白(即霍乱毒素 B 链;花生凝集素、抗硫脂的单克隆抗体 Sulph 1;以及针对无唾液酸-G(M2)的多克隆抗血清)进行探测。该方法的初步评估表明 GSL 的成功固定和测试探针的选择性结合。讨论了该方法在设计包含 GSL 用于血清诊断的共价微阵列方面的潜在用途。