Dwek R A, Ashford D A, Edge C J, Parekh R B, Rademacher T W, Wing D R, Barclay A N, Davis S J, Williams A F
Department of Biochemistry, University of Oxford, U.K.
Philos Trans R Soc Lond B Biol Sci. 1993 Oct 29;342(1299):43-50. doi: 10.1098/rstb.1993.0133.
The site-specific glycosylation of soluble recombinant variants of human and rat CD4 (sCD4) expressed in Chinese hamster ovary (CHO) cells has been characterized. The presence of identical oligosaccharides at the conserved glycosylation site in domain 3 of rat and human sCD4 and the greater abundance of oligomannose and hybrid type glycans at the non-conserved glycosylation site of rat sCD4 clearly indicate that the protein structure influences oligosaccharide processing. Comparisons of rat sCD4 glycopeptides with mutant molecules with only single glycosylation sites and with a truncated form containing only the two NH2-terminal domains, indicate that independent processing occurs at each glycosylation site and that domain interactions can also affect oligosaccharide processing. These and other analyses of sCD2 expressed in CHO cells and Thy-1 purified from various tissues suggest that the diversity of oligosaccharide structures on a protein is regulated by the location of the glycosylation sites and the nature of the target protein, cell and tissue. The functional significance of this control remains to be determined.
已对在中国仓鼠卵巢（CHO）细胞中表达的人源和大鼠源CD4可溶性重组变体（sCD4）的位点特异性糖基化进行了表征。大鼠和人源sCD4第3结构域保守糖基化位点处存在相同的寡糖，且大鼠sCD4非保守糖基化位点处的寡甘露糖和杂合型聚糖丰度更高，这清楚地表明蛋白质结构会影响寡糖加工。将大鼠sCD4糖肽与仅具有单个糖基化位点的突变分子以及仅包含两个NH2末端结构域的截短形式进行比较，表明每个糖基化位点都会独立进行加工，并且结构域间相互作用也会影响寡糖加工。对CHO细胞中表达的sCD2以及从各种组织中纯化的Thy-1进行的这些分析和其他分析表明，蛋白质上寡糖结构的多样性受糖基化位点的位置以及靶蛋白、细胞和组织的性质调控。这种调控的功能意义尚待确定。
