...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Factors determining vesicular lipid mixing induced by shortened constructs of influenza hemagglutinin.
【24h】

Factors determining vesicular lipid mixing induced by shortened constructs of influenza hemagglutinin.

机译：确定由流感血凝素的缩短构建体诱导的囊泡脂质混合的因素。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The HA2 subunit of influenza hemagglutinin is responsible for fusion of the viral and host-cell membranes during infection. An N-terminal 127 amino acid construct of HA2, FHA2-127, is shown to induce lipid mixing of large unilamellar vesicles under endosomal low pH conditions. Thus, FHA2 could serve as a good model system for biophysical studies of membrane fusion. With FHA2, we began to develop a mechanistic model which could explain how this short construct facilitates membrane fusion. In this endeavor, we studied the possible role of the kinked loop region (amino acids 105-113). A construct missing this loop, FHA2-90, although able to induce lipid mixing, has lost the sharp pH-dependent transition seen with FHA2-127 and native HA. In addition, FHA2-127 promotes extensive vesicle aggregation more effectively than FHA2-90 upon acidification. These data suggest that the kinked loop may play a pH-dependent regulatory role. To test this, we compared bis-ANS binding to the two constructs and observed that binding to FHA2-127 increases at a faster rate than FHA2-90 as the pH is decreased, indicating that the kinked loop not only is an ANS-binding site, but that it binds better at low pH. The pH dependence of this transition directly correlates with that observed in lipid mixing. Further, cysteine mutations of acidic residues in the kinked region are both fusion inactive and bind much less ANS, whereas a similar mutation of a threonine residue had little effect on fusion activity or ANS binding. This evidence lends further support to our idea that the kinked loop serves a regulatory role. To test the physiological relevance of the FHA2-127 fusion mechanism, we studied the effects of a G1E mutation, known to abolish fusion in native HA. We found that G1E-127 is fusion inactive as expected. This evidence indirectly suggests that the mechanism of FHA2-127 is perhaps physiologically relevant and from its study, we can learn much about the mechanism of native HA.
机译：流感血凝素的HA2亚基负责感染过程中病毒膜和宿主细胞膜的融合。 HA2的N端127个氨基酸构建体FHA2-127在内吞性低pH条件下可诱导大单层囊泡的脂质混合。因此，FHA2可以作为膜融合的生物物理研究的良好模型系统。利用FHA2，我们开始开发一种机制模型，该模型可以解释这种短构建体如何促进膜融合。在这项工作中，我们研究了扭结环区域（氨基酸105-113）的可能作用。缺少该环的构建体FHA2-90虽然能够诱导脂质混合，但已经失去了FHA2-127和天然HA所见的急剧的pH依赖性转变。此外，酸化后，FHA2-127比FHA2-90更有效地促进广泛的囊泡聚集。这些数据表明，扭结环可能起pH依赖性调节作用。为了测试这一点，我们比较了bis-ANS与两个构建体的结合，并观察到随着pH降低，与FHA2-127的结合以比FHA2-90更快的速率增加，这表明扭结环不仅是ANS结合位点，但在低pH值下结合效果更好。这种转变的pH依赖性与脂质混合中观察到的pH依赖性直接相关。此外，扭结区域中酸性残基的半胱氨酸突变既不融合，又结合更少的ANS，而苏氨酸残基的类似突变对融合活性或ANS结合的影响很小。该证据进一步支持了我们的观点，即扭结环起着调节作用。为了测试FHA2-127融合机制的生理相关性，我们研究了G1E突变的作用，已知该突变可消除天然HA中的融合。我们发现，G1E-127像预期的那样是融合惰性的。这些证据间接表明FHA2-127的机制可能与生理有关，从其研究中我们可以学到很多有关天然HA的机制。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号