Sheehan J P, Iorio R M, Syddall R J, Glickman R L, Bratt M A
Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655.
Virology. 1987 Dec;161(2):603-6. doi: 10.1016/0042-6822(87)90158-9.
Viruses within the Newcastle disease virus (NDV) serotype induce a wide array of disease manifestations ranging from an almost apathogenic pattern to the high mortality caused by avirulent or virulent isolates, respectively. A disulfide-linked dimer form of the NDV hemagglutinin-neuraminidase (HN) glycoprotein can be demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions for only some of these isolates. For others, indeed the majority of those we have studied, no such reducing agent-sensitive dimeric form of HN is demonstrable. Apparently, there is no causal relationship between disulfide-linked dimeric HN and virulence. Using the deduced amino acid sequence of the dimeric HN of isolate AV as a basis for selection of oligonucleotide primers, we sequenced three additional reducing agent-sensitive dimeric HN glycoproteins and eight for which a disulfide-linked dimer has not been identified, using primer extension and dideoxy sequencing. The deduced amino acid sequences reveal a strict correlation between the presence of cysteine at residue 123 and reducing agent-sensitive dimerization of HN.
新城疫病毒（NDV）血清型中的病毒可引发一系列疾病表现，从几乎无致病性的模式到分别由无毒或有毒分离株导致的高死亡率。只有部分此类分离株在非还原条件下通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳可显示出NDV血凝素-神经氨酸酶（HN）糖蛋白的二硫键连接二聚体形式。对于其他分离株，实际上是我们研究的大多数分离株，未显示出这种对还原剂敏感的HN二聚体形式。显然，二硫键连接的二聚体HN与毒力之间不存在因果关系。以分离株AV的二聚体HN推导的氨基酸序列为基础选择寡核苷酸引物，我们使用引物延伸和双脱氧测序法对另外三种对还原剂敏感的二聚体HN糖蛋白以及八种尚未鉴定出二硫键连接二聚体的糖蛋白进行了测序。推导的氨基酸序列揭示了123位残基处半胱氨酸的存在与HN对还原剂敏感的二聚化之间存在严格的相关性。
