Membrane proteins specified by herpes simplex viruses. V. Identification of an Fc-binding glycoprotein
Membrane proteins specified by herpes simplex viruses. V. Identification of an Fc-binding glycoprotein
复制标题
单纯疱疹病毒特异的膜蛋白。
作者：
Robert B. Baucke;Patrícia;G. Spear
从单纯疱疹病毒1型感染的培养细胞提取物中分离出对免疫球蛋白Fc区具有亲和力的糖蛋白，并进行实验以表征其特性，并研究它是否可以解释先前在完整的单纯疱疹病毒感染细胞表面上证明的Fc结合活性。亲和层析技术用于鉴定和分离Fc结合糖蛋白，并证明其与免疫球蛋白G-Fc相互作用的特异性。尽管通过亲和色谱法鉴定了三种可区分的Fc结合多肽，但基于蛋白水解消化产物的比较和在用放射性氨基酸短暂脉冲后每种形式的出现动力学，这三种物质似乎是相同翻译产物的不同形式。结果表明，一种多肽，命名为pE，被加工产生gE 1，gE 1又被加工产生gE 2。gE 1和gE 2都是糖基化的膜蛋白，两者都可以通过乳过氧化物酶催化的完整感染细胞的放射性碘标记，表明这些蛋白质存在于细胞的表面膜中。发现细胞表面的gE 1和gE 2的量的增加与完整感染细胞的Fc结合活性的增加平行。
A glycoprotein with affinity for the Fc region of immunoglobulin was isolated from extracts of cultured cells infected with herpes simplex virus type 1, and experiments were done to characterize its properties and to investigate whether it could account for the Fc-binding activity previously demonstrated on the surfaces of intact herpes simplex virus-infected cells. The technique of affinity chromatography was used to identify and isolate the Fc-binding glycoprotein and to demonstrate the specificity of its interaction with immunoglobulin G-Fc. Although three electrophoretically distinguishable Fc-binding polypeptides were identified by affinity chromatography, these three species appear to be different forms of the same translation product, based on comparisons of proteolytic digestion products and on the kinetics of appearance of each form after a brief pulse with radioactive amino acids. The results suggest that one polypeptide, designated pE, is processed to yield gE1, which is in turn processed to yield gE2. Both gE1 and gE2 are glycosylated membrane proteins and both can be labeled by the lactoperoxidase-catalyzed radioiodination of intact infected cells, indicating the presence of these proteins in surface membranes of the cells. Increases in the amounts of gE1 and gE2 at the cell surface were found to parallel the increase in Fc-binding activity of intact infected cells.