Li Y, Luo L, Rasool N, Kang C Y
Department of Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ontario, Canada.
J Virol. 1993 Jan;67(1):584-8. doi: 10.1128/JVI.67.1.584-588.1993.
Conflicting results have been reported regarding the role of carbohydrate on human immunodeficiency virus (HIV) envelope glycoprotein gp120 in CD4 receptor binding. Glycosylated, deglycosylated, and nonglycosylated forms of HIV type 1 (HIV-1) and HIV-2 gp120s were used to examine CD4 receptor-binding activity. Nonglycosylated forms of gp120 generated either by deletion of the signal sequence of HIV-1 gp120 or by synthesis in the presence of tunicamycin failed to bind to CD4. In contrast, highly mannosylated gp120 bound to soluble CD4 molecules well. Enzymatic removal of carbohydrate chains from glycosylated gp120 by endoglycosidase H or an endoglycosidase F/N glycanase mixture had no effect on the ability of gp120 to bind CD4. An experiment which measured the ability of gp120 to bind to CD4 as an assay of the proper conformation of gp120 showed that carbohydrate chains on gp120 are not required for the interaction between gp120 and CD4 but that N-linked glycosylation is essential for generation of the proper conformation of gp120 to provide a CD4-binding site.
关于碳水化合物在人类免疫缺陷病毒（HIV）包膜糖蛋白gp120与CD4受体结合中的作用，已有相互矛盾的报道。使用1型HIV（HIV-1）和HIV-2 gp120的糖基化、去糖基化和非糖基化形式来检测CD4受体结合活性。通过缺失HIV-1 gp120的信号序列或在衣霉素存在下合成产生的非糖基化形式的gp120未能与CD4结合。相比之下，高度甘露糖基化的gp120与可溶性CD4分子结合良好。用内切糖苷酶H或内切糖苷酶F/N聚糖酶混合物对糖基化gp120进行酶促去除碳水化合物链，对gp120结合CD4的能力没有影响。一项以gp120结合CD4的能力作为gp120正确构象检测的实验表明，gp120与CD4之间的相互作用不需要gp120上的碳水化合物链，但N-连接糖基化对于产生gp120的正确构象以提供CD4结合位点至关重要。
