Staudacher Erika, Stepan Herwig, Gutternigg Martin
University of Natural Resources and Applied Life Sciences, Vienna Department of Chemistry Division of Biochemistry Glycobiology Muthgasse 18 A-1190 Vienna Austria TEL: 0043-1-36006-6063 FAX: 0043-1-36006-6059
Curr Top Biochem Res. 2009 Dec;11(2):29-39.
Glycosylation plays an important role in several types of recognition processes associated with fertilisation and development, allergies, pathological events and cell death. Whereas the amino acid sequence of a protein is fixed by the DNA, the glycosylation abilities depend on enzymes and substrates currently present in the cell.During the last decades our knowledge on glycosylation - the structure of glycans as well as the corresponding biochemical pathways including the responsible enzymes - especially on glycans of mammalian origin increased enormously. The glycosylation capabilities of other species were under investigation only if their glycans were for any reason connected to human life (e.g. some recognition processes of pathogens or allergy on food or plant glycans) or if they were potent candidates for cell culture systems for the expression of therapeutic agents (some insect, yeast and plant cells). However, in the meantime there is an increasing interest also in invertebrate glycosylation.Snails in particular show a broad spectrum of glycosylation abilities within their N-glycosylation pattern. In one case this has been shown to be involved in an intermediate host - parasite recognition process. For other snail species, it was found that they share many structural elements of N-glycans with mammals, plants, insects or nematodes. Sometimes several of these elements are present within one single structure.Here we present an overview of the current knowledge of N-glycosylation of snails, the glycan structures and the corresponding enzymes involved in the biosynthetic glycosylation pathway.
糖基化在与受精、发育、过敏、病理事件及细胞死亡相关的多种识别过程中发挥着重要作用。蛋白质的氨基酸序列由DNA固定，而糖基化能力则取决于细胞中当前存在的酶和底物。在过去几十年里，我们对糖基化的认识——聚糖的结构以及包括相关酶在内的相应生化途径——尤其是对哺乳动物来源聚糖的认识大幅增加。只有当其他物种的聚糖因某种原因与人类生活相关（例如病原体的某些识别过程或对食物或植物聚糖的过敏反应），或者它们是用于表达治疗剂的细胞培养系统的有力候选者（一些昆虫、酵母和植物细胞）时，才会对其糖基化能力进行研究。然而，与此同时，人们对无脊椎动物的糖基化也越来越感兴趣。特别是蜗牛，其N-糖基化模式展现出广泛的糖基化能力。在一个案例中，这已被证明参与中间宿主-寄生虫的识别过程。对于其他蜗牛物种，发现它们与哺乳动物、植物、昆虫或线虫共享许多N-聚糖的结构元件。有时，这些元件中的几个会存在于单个结构中。在此，我们概述了目前关于蜗牛N-糖基化、聚糖结构以及生物合成糖基化途径中相关酶的知识。
