Young J K, Hicks R P, Wright G E, Morrison T G
Department of Molecular Genetics and Microbiology, University of Massachusetts Medical Center, Worcester 01655, USA.
Virology. 1997 Nov 24;238(2):291-304. doi: 10.1006/viro.1997.8834.
To investigate the molecular mechanisms involved in paramyxovirus-induced cell fusion, the function and structure of a peptide with a 20-amino-acid sequence from the leucine zipper region (heptad repeat region 2) of the Newcastle disease virus fusion protein (F) were characterized. A peptide with the sequence ALDKLEESNSKLDKVNVKLT (amino acids 478-497 of the F protein) was found to inhibit syncytia formation after virus infection and after transfection of Cos cells with the HN (hemagglutinin-neuraminidase) and F protein cDNAs. Using an F protein gene that requires addition of exogenous trypsin for cleavage, it was shown that the peptide exerted its inhibitory effect prior to cleavage. The three-dimensional conformation of the peptide in aqueous solution was determined through the use of NMR and molecular modeling. Results showed that the peptide formed a helix with properties between an alpha-helix and a 3(10)-helix and that leucine residues aligned along one face of the helix. Side chain salt bridges and hydrogen bonds likely contributed to the stability of the peptide secondary structure. Analysis of the aqueous solution conformation of the peptide suggested mechanisms for specificity of interaction with the intact F protein.
为了研究副粘病毒诱导细胞融合的分子机制，对来自新城疫病毒融合蛋白（F）亮氨酸拉链区（七肽重复区域2）的一段含20个氨基酸序列的肽段的功能和结构进行了表征。发现一段序列为ALDKLEESNSKLDKVNVKLT（F蛋白的氨基酸478 - 497）的肽段在病毒感染后以及用HN（血凝素 - 神经氨酸酶）和F蛋白cDNA转染Cos细胞后可抑制多核巨细胞的形成。使用一种需要添加外源性胰蛋白酶进行切割的F蛋白基因，结果表明该肽段在切割之前就发挥了其抑制作用。通过核磁共振（NMR）和分子建模确定了该肽段在水溶液中的三维构象。结果表明，该肽段形成了一种介于α - 螺旋和3(10) - 螺旋之间的螺旋结构，且亮氨酸残基沿螺旋的一个面排列。侧链盐桥和氢键可能有助于肽段二级结构的稳定性。对该肽段水溶液构象的分析提示了其与完整F蛋白相互作用特异性的机制。
