CCR5-mediated human immunodeficiency virus entry depends on an amino-terminal gp120-binding site and on the conformational integrity of all four extracellular domains
CCR5-mediated human immunodeficiency virus entry depends on an amino-terminal gp120-binding site and on the conformational integrity of all four extracellular domains
复制标题
DOI：
10.1128/jvi.73.2.1645-1648.1999
复制
发表时间：
1999-02-01
影响因子：
5.4
通讯作者：
Dragic, T
中科院分区：
文献类型：
--
作者：
Genoud, S;Kajumo, F;Dragic, T
CCR 5的人类免疫缺陷病毒1型辅助受体活性取决于其氨基末端结构域中的某些极性和带电残基。由于嵌合受体的研究表明，CCR 5的细胞外环也参与了病毒的融合和进入，我们已经探讨了在这些地区的大体积，极性和非极性残基的作用。选择的氨基酸在三个细胞外环分别改变做丙氨酸，并在荧光素酶报告病毒为基础的进入试验中测试的突变型CCR 5蛋白的辅助受体活性。我们发现CCR 5细胞外环中的半胱氨酸对辅助受体活性是必不可少的。然而，所有其他丙氨酸取代对辅助受体功能只有轻微（2 - 3倍）影响。我们还证明，当前19个氨基酸残基的氨基末端区域从其余的CCR 5分离;通过插入甘氨酸/丝氨酸间隔脯氨酸19和半胱氨酸20之间，辅助受体功能下降。与我们以前的研究一起，这些数据表明，氨基末端gp 120结合位点和细胞外结构域的几何形状在病毒进入中发挥作用。
The human immunodeficiency virus type 1 coreceptor activity of CCR5 depends on certain polar and charged residues in its amino-terminal domain. Since studies of chimeric receptors have indicated that the extracellular loops of CCR5 are also involved in viral fusion and entry, we have explored the role of bulky, polar and nonpolar residues in these regions. Selected amino acids in the three extracellular loops were individually changed do alanines, and the coreceptor activities of the mutant CCR5 proteins were tested in a luciferase reporter virus-based entry assay. We found that the cysteines in the extracellular loops of CCR5 are essential for coreceptor activity. However, only minor (two- to threefold) effects on coreceptor function were noted for all of the other alanine substitutions. We also demonstrated that when the first 19 residues of the amino-terminal region were separated from the rest of CCR5; by insertion of glycine/serine spacers between proline 19 and cysteine 20, coreceptor function decreased. Together with our previous studies, these data indicate that both an amino-terminal gp120-binding site and extracellular domain geometry play a role in viral entry.