CYST WALL ENDOPROTEASES OF ENTAMOEBA INVADENS AND ENTAMOEBA HISTOLYTICA

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 溶组织内阿米巴是引起阿米巴痢疾和肝脓肿的原生生物，其N-聚糖由于多种原因而引起人们极大的兴趣。E. histolytica产生一种不寻常的截短N-聚糖前体（Man（5）GlcNAc（2）），几乎没有核苷酸糖转运蛋白，表面被凝集素伴刀豆球蛋白A覆盖。本文采用生物化学和质谱方法研究了大肠杆菌N-聚糖的生物合成和最终N-聚糖的合成。组织溶解，得出以下结论。未加工Man（5）GlcNAc（2），这是最丰富的E.溶组织菌N-聚糖在大肠杆菌表面聚集成帽状。通过N-聚糖特异性抗逆转录病毒凝集素cyanovirin-N. Glc（1）Man（5）GlcNAc（2）也存在于成熟的N-聚糖中，它由UDP-Glc：糖蛋白葡糖基转移酶产生，是保守的N-聚糖依赖性内质网蛋白质折叠质量控制系统的一部分。苦马豆素敏感的α-甘露糖苷酶将一些N-聚糖修剪成双触角Man（3）GlcNAc（2）。E.通过将α 1，2-连接的Gal添加到小寡聚甘露糖聚糖的两个臂上来制备溶组织剂，并且Gal残基被一个或多个Glc封端。综上所述，E.溶组织菌N-聚糖包括未加工的Man（5）GlcNAc（2），它是氰威菌素-N的靶标，以及含有Gal和Glc的独特复杂N-聚糖。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. N-Glycans of Entamoeba histolytica, the protist that causes amebic dysentery and liver abscess, are of great interest for multiple reasons. E. histolytica makes an unusual truncated N-glycan precursor (Man(5)GlcNAc(2)), has few nucleotide sugar transporters, and has a surface that is capped by the lectin concanavalin A. Here, biochemical and mass spectrometric methods were used to examine N-glycan biosynthesis and the final N-glycans of E. histolytica with the following conclusions. Unprocessed Man(5)GlcNAc(2), which is the most abundant E. histolytica N-glycan, is aggregated into caps on the surface of E. histolytica by the N-glycan-specific, anti-retroviral lectin cyanovirin-N. Glc(1)Man(5)GlcNAc(2), which is made by a UDP-Glc: glycoprotein glucosyltransferase that is part of a conserved N-glycan-dependent endoplasmic reticulum quality control system for protein folding, is also present in mature N-glycans. A swainsonine-sensitive alpha-mannosidase trims some N-glycans to biantennary Man(3)GlcNAc(2). Complex N-glycans of E. histolytica are made by the addition of alpha1,2-linked Gal to both arms of small oligomannose glycans, and Gal residues are capped by one or more Glc. In summary, E. histolytica N-glycans include unprocessed Man(5)GlcNAc(2), which is a target for cyanovirin-N, as well as unique, complex N-glycans containing Gal and Glc.