Mizuochi T, Loveless R W, Lawson A M, Chai W, Lachmann P J, Childs R A, Thiel S, Feizi T
Section of Glycoconjugate Research Medical Research Council Clinical Research Centre, Harrow, Middlesex, United Kingdom.
J Biol Chem. 1989 Aug 15;264(23):13834-9.
This report describes the preparation of a library of oligosaccharide probes (neoglycolipids) from N-glycosylated proteins, characterization of the probes by liquid secondary ion mass spectrometry, and investigation of their reactions with 125I-labeled bovine serum conglutinin by chromatogram binding assays. The results, together with additional binding studies using neoglycolipids derived from purified complex type bi-, tri-, and tetraantennary oligosaccharides from urine, or their glycosidase-treated products, have shown that the combining specificity of conglutinin includes structures not only on high mannose-type oligosaccharides but also on hybrid- and complex-type chains. With high mannose-type oligosaccharides there is increased reactivity from the Man5 to the Man8 structures, indicating a preference for the terminal Man alpha 1-2 sequence. With complex- and hybrid-type oligosaccharides, the requirements for binding are the presence of nonreducing terminal N-acetylglucosamine or mannose residues, but the presence of a bisecting N-acetylglucosamine residue may inhibit binding. From these results it is deduced that the reactivity of conglutinin with the complement glycopeptide iC3b rather than the intact glycoprotein C3 is due to the oligosaccharide accessibility rendered by proteolysis in the complement cascade.
本报告描述了从N-糖基化蛋白制备寡糖探针（新糖脂）文库，通过液体二次离子质谱对探针进行表征，以及通过色谱结合分析研究它们与125I标记的牛血清胶固素的反应。这些结果，连同使用从尿液中纯化的复合型二、三、四天线寡糖衍生的新糖脂或其糖苷酶处理产物进行的额外结合研究表明，胶固素的结合特异性不仅包括高甘露糖型寡糖上的结构，还包括杂合型和复合型链上的结构。对于高甘露糖型寡糖，从Man5到Man8结构的反应性增加，表明对末端Manα1-2序列有偏好。对于复合型和杂合型寡糖，结合的要求是存在非还原末端N-乙酰葡糖胺或甘露糖残基，但存在平分的N-乙酰葡糖胺残基可能会抑制结合。从这些结果推断，胶固素与补体糖肽iC3b而非完整糖蛋白C3的反应性是由于补体级联反应中蛋白水解导致的寡糖可及性。
