Glycosyltransferases involved in type 1 chain and Lewis antigen biosynthesis exhibit glycan and core chain specificity
Glycosyltransferases involved in type 1 chain and Lewis antigen biosynthesis exhibit glycan and core chain specificity
复制标题
DOI：
10.1093/glycob/cwj090
复制
发表时间：
2006-07-01
期刊：
影响因子：
4.3
通讯作者：
Lofling, Jonas
中科院分区：
文献类型：
--
作者：
Holgersson, Jan;Lofling, Jonas
唾液酸化刘易斯A（Sle（a））、刘易斯A（Le（a））和刘易斯B（Le（B））已经在许多不同的生物学背景下进行了研究，例如在微生物粘附和癌症中。它们的生物合成是复杂的，涉及β 1，3-半乳糖基转移酶（β 3Gal-Ts）和α 2-和/或α 4-岩藻糖基转移酶（Fuc-Ts）的联合作用。此外，具有不同核心结构的0-聚糖已被鉴定，并且β 3Gal-Ts和Fuc-Ts使用这些作为底物的能力尚未解决。因此，为了检查参与S莱亚、莱亚和Leb合成的酶的体内特异性，我们用相关的人糖基转移酶瞬时转染CHO-K1细胞，并在分泌的报告蛋白上，使用蛋白质印迹和Le-specific抗体检测N-和O-连接聚糖上产生的刘易斯抗原。β 3Gal-T1、β 3Gal-T2和β 3Gal-T5可以在N-连接的聚糖上合成I型链，但只有β 3Gal-T5对O-连接的聚糖起作用。后一种酶可以使用核心2和核心3前体结构。此外，FUT 5和FUT 3在莱亚和Leb合成中的特异性不同，FUT 5仅在核心2上岩藻糖基化H I型，但FUT 3在核心3上岩藻糖基化H 1型比在核心2上有效得多。最后，发现FUT 1和FUT 2均在N-和O-连接结构的1型链上指导α 2-岩藻糖基化。这些知识使我们能够用聚糖和核心链特异性刘易斯抗原取代来设计重组糖蛋白。这些工具对于研究Le（B）结合凝集素（如幽门螺杆菌粘附素和DC-SIGN）的精细碳水化合物特异性将是重要的，并且也可以证明作为治疗剂是有用的。
Sialyl Lewis A (SLe(a)), Lewis A (Le(a)), and Lewis B (Le(b) have been studied in many different biological contexts, for example in microbial adhesion and cancer. Their biosynthesis is complex and involves beta 1,3-galactosyltransferases (beta 3Gal-Ts) and a combined action of alpha 2- and/or alpha 4-fucosyltransferases (Fuc-Ts). Further, O-glycans with different core structures have been identified, and the ability of beta 3Gal-Ts and Fuc-Ts to use these as substrates has not been resolved. Therefore, to examine the in vivo specificity of enzymes involved in SLea, Lea, and Leb synthesis, we have transiently transfected CHO-K1 cells with relevant human glycosyltransferases and, on secreted reporter proteins, detected the resulting Lewis antigens on N- and O-linked glycans using western blotting and Le-specific antibodies. beta 3Gal-T1, -T2, and -T5 could synthesize type I chains on N-linked glycans, but only beta 3Gal-T5 worked on O-linked glycans. The latter enzyme could use both core 2 and core 3 precursor structures. Furthermore, the specificity of FUT5 and FUT3 in Lea and Leb synthesis was different, with FUT5 fucosylating H type I only on core 2, but FUT3 fucosylating H type 1 much more efficient on core 3 than on core 2. Finally, FUT1 and FUT2 were both found to direct alpha 2-fucosylation on type 1 chains on both N- and O-linked structures. This knowledge enables us to engineer recombinant glycoproteins with glycan- and core chain-specific Lewis antigen substitution. Such tools will be important for investigations on the fine carbohydrate specificity of Le(b)-binding lectins, such as Helicobacter pylori adhesins and DC-SIGN, and may also prove useful as therapeutics.