A single amino acid changes enhances the fusion promotion activity of human parainfluenza virus type 1 hemagglutinin-neuraminidase glycoprotein.
A single amino acid changes enhances the fusion promotion activity of human parainfluenza virus type 1 hemagglutinin-neuraminidase glycoprotein.
复制标题
单个氨基酸的改变增强了人副流感病毒1型血凝素-神经氨酸酶糖蛋白的融合促进活性。
DOI：
10.1006/viro.1995.1299
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发表时间：
1995
期刊：
影响因子：
3.7
通讯作者：
Portner,A
中科院分区：
文献类型：
--
作者：
Bousse,T;Takimoto,T;Portner,A
我们实验室分离的人副流感病毒1型临床分离株在CV-1细胞中可诱导明显不同程度的合胞体形成。高融合和低融合菌株的序列分析表明，血凝素-神经氨酸酶（HN）蛋白是负责融合活性的差异。我们利用菌株的差异，以确定特定的氨基酸残基的HN蛋白，这是负责低和高融合活性的HN蛋白的两个低融合菌株8389和45785，和高融合菌株C35，在HeLa T4+细胞中表达和它们的融合促进活性进行了比较。当与C35 F共表达时，来自低融合性病毒的HN与比C95 HN低得多的融合活性相关，表明HN蛋白修饰了病毒的融合性。为了确定HN蛋白的区域负责这种差异，我们构建了一系列嵌合HN cDNA结合8389和C35序列。所有在蛋白质的中心36%中含有C35序列的嵌合HN都表现出高的融合促进活性。通过定点诱变的进一步分析表明，在位置242处的单个Asn至Lys取代将8389 HN转化为高度促进融合的分子。因此，FIN分子的球状头部参与融合促进活性。
Clinical isolates of human parainfluenza virus type 1 in our laboratory were found to induce significantly different degrees of syncytium formation in CV-1 cells. Sequence analysis of high- and low-fusion strains suggested that the hemagglutinin-neuraminidase (HN) protein was responsible for the differences in fusion activity. We exploited the strain differences to define the specific amino acid residues of the HN protein which were responsible for the low and high fusion activities The HN proteins of the two low-fusogenic strains 8389 and 45785, and the highly fusogenic strain C35, were expressed in HeLa T4+cells and their fusion promotion activities were compared. When coexpressed with C35 F, HNs from the low-fusogenic viruses were associated with much lower fusion activity then was C95 HN, suggesting that the HN proteins modified the fusogenicity of the viruses. To identify the region of the HN protein responsible for this difference, we constructed a series of chimeric HN cDNAs combining 8389 and C35 sequences. All chimetic HNs that contained C35 sequence in the central 36% of the protein exhibited high fusion promotion activity. Further analysis by site-directed mutagenesis showed that a single Asn-to-Lys substitution at position 242 converted 8389 HN to a highly fusion-promoting molecule. Thus, the globular head of the FIN molecule is involved in fusion promotion activity.