FUSION ACTIVITY OF INFLUENZA VIRUS-PR8/34 CORRELATES WITH A TEMPERATURE-INDUCED CONFORMATIONAL CHANGE WITHIN THE HEMAGGLUTININ ECTODOMAIN DETECTED BY PHOTOCHEMICAL LABELING
FUSION ACTIVITY OF INFLUENZA VIRUS-PR8/34 CORRELATES WITH A TEMPERATURE-INDUCED CONFORMATIONAL CHANGE WITHIN THE HEMAGGLUTININ ECTODOMAIN DETECTED BY PHOTOCHEMICAL LABELING
复制标题
DOI：
10.1021/bi00223a019
复制
发表时间：
1991-03-05
期刊：
影响因子：
2.9
通讯作者：
MISCHLER, R
中科院分区：
文献类型：
--
作者：
BRUNNER, J;ZUGLIANI, C;MISCHLER, R
流感病毒与膜的融合由病毒刺突蛋白血凝素（HA）催化。在弱酸性条件下（约pH 5），该蛋白质发生构象变化，引发“融合肽”（HA 2多肽链的疏水性N-末端片段）暴露。将该片段插入靶膜（或病毒膜？）很可能代表了核聚变途径上的关键沿着一步，但细节还远不清楚。光反应性磷脂1-棕榈酰-2-[11-[4-[3-（4-氨基苯基）-2-甲基-2-氧代戊基]氨基]-2-氧代戊基][（三氟甲基）二氮丙啶基]苯基][2-H-3]十一酰基]-sn-甘油基-3-磷酸胆碱（[H-3]PTPC/11）插入到大单层囊泡（LUV）的双层中，使我们能够研究在“预融合”条件下病毒与囊泡的相互作用，（pH 5; 0 ℃）和熔融过程本身仅在升高的温度（> 15-20 ℃）下发生。尽管在pH 5和0 ℃下观察到病毒与LUV结合，但HA 2的标记非常弱（<最初存在的放射性的0.002%）。相反，融合可以通过该多肽链的共价标记容易地监测。我们还研究了温度对菠萝蛋白酶增溶HA（BHA）与囊泡的酸诱导（pH 5）相互作用的影响。BHA 2多肽链的标记被发现与整个病毒的融合活性的温度依赖性显示出显着的相关性。温度诱导的结构变化似乎是关键的BHA与膜的相互作用和完整病毒的融合活性的表达。
Fusion of influenza viruses with membranes is catalyzed by the viral spike protein hemagglutinin (HA). Under mildly acidic conditions (approximately pH 5) this protein undergoes a conformational change that triggers the exposure of the "fusion peptide", the hydrophobic N-terminal segment of the HA2 polypeptide chain. Insertion of this segment into the target membrane (or viral membrane?) is likely to represent a key step along the fusion pathway, but the details are far from being clear. The photoreactive phospholipid 1-palmitoyl-2-[11-[4-[3-(trifluoromethyl)diazirinyl]phenyl][2-H-3]undecanoyl]-sn-glycero-3-phosphocholine ([H-3]PTPC/11), inserted into the bilayer of large unilamellar vesicles (LUVs), allowed us to investigate both the interaction of viruses with the vesicles under "prefusion" conditions (pH 5; 0-degrees-C) and the fusion process itself occurring at elevated temperatures (> 15-20-degrees-C) only. Despite the observed binding of viruses to LUVs at pH 5 and 0-degrees-C, labeling of HA2 was very weak (< 0.002% of the radioactivity originally present). In contrast, fusion could be readily monitored by the covalent labeling of that polypeptide chain. We have studied also the effect of temperature on the acid-induced (pH 5) interaction of bromelain-solubilized HA (BHA) with vesicles. Labeling of the BHA2 polypeptide chain was found to show a remarkable correlation with the temperature dependence of the fusion activity of whole viruses. A temperature-induced structural change appears to be critical for both the interaction of BHA with membranes and the expression of fusion activity of intact viruses.