A chimeric protein of simian immunodeficiency virus envelope glycoprotein gp140 and Escherichia coli aspartate transcarbamoylase
A chimeric protein of simian immunodeficiency virus envelope glycoprotein gp140 and Escherichia coli aspartate transcarbamoylase
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DOI：
10.1128/jvi.78.9.4508-4516.2004
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发表时间：
2004-05-01
影响因子：
5.4
通讯作者：
Wiley, DC
中科院分区：
文献类型：
--
作者：
Chen, B;Cheng, YF;Wiley, DC
人类免疫缺陷病毒和相关猿猴免疫缺陷病毒（SIV）的包膜糖蛋白通过融合病毒和靶细胞膜介导病毒进入宿主细胞。我们报道了 gp140（也称为 gp160e）的表达、纯化和表征，gp140 是 SIV 包膜糖蛋白 gp160 的可溶性三聚体胞外域（B. Chen 等人，J. Biol. Chem. 275:34946-34953, 2000）。我们现已表达并纯化了 SIV gp140 及其变体与大肠杆菌天冬氨酸转氨甲酰酶 (ATCase) 催化亚基 (C) 的嵌合蛋白。融合蛋白 (SIV gp140-ATC) 结合病毒受体 CD4 和许多对 SIV gp140 具有特异性的单克隆抗体。嵌合分子还具有 ATCase 活性，这需要 ATCase C 链的三聚化。因此，融合蛋白是三聚体。当添加 ATCase 调节亚基二聚体 (R-2) 时，融合蛋白会按照 C、R、ATCase 结构的预期组装成三聚体的二聚体。负染色电子显微镜揭示了 SIV gp140 和 SIV gp140-ATC 的尖峰特征。融合蛋白的产生可以增强通过电子冷冻显微镜或X射线晶体学确定包膜糖蛋白结构的可能性。
The envelope glycoproteins of the human immunodeficiency virus and the related simian immunodeficiency virus (SIV) mediate viral entry into host cells by fusing viral and target cell membranes. We have reported expression, purification, and characterization of gp140 (also called gp160e), the soluble, trimeric ectodomain of the SIV envelope glycoprotein, gp160 (B. Chen et al., J. Biol. Chem. 275:34946-34953, 2000). We have now expressed and purified chimeric proteins of SIV gp140 and its variants with the catalytic subunit (C) of Escherichia coli aspartate transcarbamoylase (ATCase). The fusion proteins (SIV gp140-ATC) bind viral receptor CD4 and a number of monoclonal antibodies specific for SIV gp140. The chimeric molecule also has ATCase activity, which requires trimerization of the ATCase C chains. Thus, the fusion protein is trimeric. When ATCase regulatory subunit dimers (R-2) are added, the fusion protein assembles into dimers of trimers as expected from the structure of C,R, ATCase. Negative-stain electron microscopy reveals spikey features of both SIV gp140 and SIV gp140-ATC. The production of the fusion proteins may enhance the possibilities for structure determination of the envelope glycoprotein either by electron cryomicroscopy or X-ray crystallography.