The Highly Conserved Glycan at Asparagine 260 of HIV-1 gp120 Is Indispensable for Viral Entry
The Highly Conserved Glycan at Asparagine 260 of HIV-1 gp120 Is Indispensable for Viral Entry
复制标题
DOI：
10.1074/jbc.m111.274456
复制
发表时间：
2011-12-16
影响因子：
4.8
通讯作者：
Balzarini, Jan
中科院分区：
文献类型：
--
作者：
Francois, Katrien O.;Balzarini, Jan
碳水化合物结合剂与HIV-1包膜gp 120的N-聚糖结合并阻止病毒进入。碳水化合物结合剂可以选择具有缺失的包膜聚糖的突变病毒。并非所有糖基化基序都突变到相同程度。定点突变显示，破坏高度保守的（260）NGS（262）糖基化基序的缺失导致非感染性病毒颗粒。在N260 Q突变型gp 120病毒株的情况下，我们观察到显著较低的CD 4结合，这是由病毒颗粒中gp 120和gp 41的显著较低表达引起的。此外，在293 T细胞中表达的突变N260 Q HIV-1包膜在与U87.CD4.CXCR4.CCR 5细胞共培养中不能形成合胞体，这是由于转染的293 T细胞表面上的包膜蛋白的较低表达。这种N-聚糖缺失对病毒感染性的有害后果不能通过在该氨基酸附近产生新的糖基化位点来补偿，从而使该未覆盖的包膜表位易于中和抗体结合。因此，HIV-1的gp 120包膜中的Asn-260聚糖代表了靶向自杀药物或抗体的热点，以有效地中和广泛的病毒株。
Carbohydrate-binding agents bind to the N-glycans of HIV-1 envelope gp120 and prevent viral entry. Carbohydrate-binding agents can select for mutant viruses with deleted envelope glycans. Not all glycosylation motifs are mutated to the same extent. Site-directed mutagenesis revealed that deletions destroying the highly conserved (260)NGS(262) glycosylation motif resulted in non-infectious virus particles. We observed a significant lower CD4 binding in the case of the N260Q mutant gp120 virus strains, caused by a strikingly lower expression of gp120 and gp41 in the virus particle. In addition, the mutant N260Q HIV-1 envelope expressed in 293T cells was unable to form syncytia in co-cultures with U87.CD4.CXCR4.CCR5 cells, due to the lower expression of envelope protein on the surface of the transfected 293T cells. The detrimental consequence of this N-glycan deletion on virus infectivity could not be compensated for by the creation of novel glycosylation sites near this amino acid, leaving this uncovered envelope epitope susceptible to neutralizing antibody binding. Thus, the Asn-260 glycan in the gp120 envelope of HIV-1 represents a hot spot for targeting suicidal drugs or antibodies in a therapeutic effort to efficiently neutralize a broad array of virus strains.