Young J K, Li D, Abramowitz M C, Morrison T G
Department of Chemistry, Colgate University, Hamilton, New York, USA.
J Virol. 1999 Jul;73(7):5945-56. doi: 10.1128/JVI.73.7.5945-5956.1999.
Typical of many viral fusion proteins, the sequence of the Newcastle disease virus (NDV) fusion protein has several heptad repeat regions. One, HR1, is located just carboxyl terminal to the fusion peptide, while the other, HR2, is located adjacent to the transmembrane domain. The structure and function of a synthetic peptide with a sequence from the region of the NDV HR1 region (amino acids 150 to 173) were characterized. The peptide inhibited fusion with a half-maximal concentration of approximately 2 microM; however, inhibition was observed only if the peptide was added prior to protease activation of the fusion protein. This inhibition was virus specific since the peptide had minimal effect on fusion directed by the Sendai virus glycoproteins. To explore the mechanism of action, the potential HR1 peptide interaction with a previously characterized fusion inhibitory peptide with a sequence from the HR2 domain (J. K. Young, R. P. Hicks, G. E. Wright, and T. G. Morrison, Virology 238:291-304, 1997) was characterized. The results demonstrated an interaction between the two peptides both functionally and directly. First, while the individual peptides each inhibit fusion, equimolar mixtures of the two peptides had minimal effect on fusion, suggesting that the two peptides form a complex preventing their interaction with a target protein. Second, an HR2 peptide covalently linked with biotin was found to bind specifically to HR1 peptide in a Western blot. The structure of the HR1 peptide was analyzed by nuclear magnetic resonance spectroscopy and found to be an alpha helix.
许多病毒融合蛋白都具有典型特征，新城疫病毒（NDV）融合蛋白的序列有几个七肽重复区域。其中一个，HR1，位于融合肽的羧基末端，而另一个，HR2，位于跨膜结构域附近。对一段来自NDV HR1区域（氨基酸150至173）的合成肽的结构和功能进行了表征。该肽抑制融合的半数最大浓度约为2 microM；然而，只有在融合蛋白经蛋白酶激活之前添加该肽时才观察到抑制作用。这种抑制具有病毒特异性，因为该肽对仙台病毒糖蛋白介导的融合作用极小。为了探究其作用机制，对潜在的HR1肽与先前表征的来自HR2结构域的融合抑制肽（J.K.扬、R.P.希克斯、G.E.赖特和T.G.莫里森，《病毒学》238:291 - 304，1997）之间的相互作用进行了表征。结果表明这两种肽在功能上和直接相互作用方面都存在相互作用。首先，虽然单个肽各自都抑制融合，但两种肽的等摩尔混合物对融合的影响极小，这表明这两种肽形成了一个复合物，阻止它们与靶蛋白相互作用。其次，在蛋白质印迹中发现与生物素共价连接的HR2肽能特异性结合HR1肽。通过核磁共振光谱分析了HR1肽的结构，发现其为α螺旋。
