Carbohydrates form one of the major groups of biological macromolecules in living organisms. Many biological processes including protein folding, stability, immune response, and receptor activation are regulated by glycosylation. Fucosylation of proteins regulates such processes and is associated with various diseases including autoimmunity and cancer. Mass spectrometry efficiently identifies structures of fucosylated glycans or sites of core fucosylated N-glycopeptides but quantification of the glycopeptides remains less explored. We performed experiments that facilitate quantitative analysis of the core fucosylation of proteins with partial structural resolution of the glycans and we present results of the mass spectrometric SWATH-type DIA analysis of relative abundances of the core fucosylated glycoforms of 45 glycopeptides derived from 18 serum proteins in liver disease of different etiologies. Our results show that a combination of soft fragmentation with exoglycosidases is efficient at the assignment and quantification of the core fucosylated N-glycoforms at specific sites of protein attachment. In addition, our results show that disease-associated changes in core fucosylation are peptide-dependent and further differ by branching of the core fucosylated glycans. Further studies are needed to verify whether tri- and tetra-antennary core fucosylated glycopeptides could be used as markers of liver disease progression.

中文翻译：

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使用外切糖苷酶辅助的独立于数据的LC-MS / MS分析肝脏疾病进展中的位点和结构特异性核心岩藻糖基化

碳水化合物是活生物体中生物大分子的主要组成部分之一。许多生物过程，包括蛋白质折叠，稳定性，免疫反应和受体活化，都受到糖基化作用的调节。蛋白质的岩藻糖基化调节这种过程，并与包括自身免疫和癌症在内的多种疾病有关。质谱有效地鉴定了岩藻糖基化聚糖的结构或核心岩藻糖基化的N-糖肽的位点，但糖肽的定量研究仍然较少。我们进行了有助于定量分析具有部分聚糖结构的蛋白质核心岩藻糖基化作用的实验，并提出了质谱SWATH型DIA分析法的结果，该分析法分析了来自18种血清蛋白的45种糖肽核心岩藻糖基化糖型的相对丰度。不同病因的肝病。我们的结果表明，软片段与糖苷外切酶的结合可以有效地在蛋白质附着的特定位点分配和定量岩藻糖基化的N-糖型核心。此外，我们的结果表明，核心岩藻糖基化的疾病相关变化是肽依赖性的，并且通过核心岩藻糖基化聚糖的分支而进一步不同。