Schiff L A, Nibert M L, Co M S, Brown E G, Fields B N
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115.
Mol Cell Biol. 1988 Jan;8(1):273-83. doi: 10.1128/mcb.8.1.273-283.1988.
By atomic absorption analysis, we determined that the reovirus outer capsid protein sigma 3, which binds double-stranded RNA (dsRNA), is a zinc metalloprotein. Using Northwestern blots and a novel zinc blotting technique, we localized the zinc- and dsRNA-binding activities of sigma 3 to distinct V8 protease-generated fragments. Zinc-binding activity was contained within an amino-terminal fragment that contained a transcription factor IIIA-like zinc-binding sequence, and dsRNA-binding activity was associated with a carboxy-terminal fragment. By these techniques, new zinc- and dsRNA-binding activities were also detected in reovirus core proteins. A sequence similarity was observed between the catalytic site of the picornavirus proteases and the transcription factor IIIA-like zinc-binding site within sigma 3. We suggest that the zinc- and dsRNA-binding activities of sigma 3 may be important for its proposed regulatory effects on viral and host cell transcription and translation.
通过原子吸收分析，我们确定呼肠孤病毒的外衣壳蛋白σ3是一种锌金属蛋白，该蛋白可结合双链RNA（dsRNA）。使用蛋白质印迹法和一种新型的锌印迹技术，我们将σ3的锌结合和dsRNA结合活性定位到不同的V8蛋白酶产生的片段上。锌结合活性存在于一个氨基末端片段中，该片段包含一个类转录因子IIIA锌结合序列，而dsRNA结合活性与一个羧基末端片段相关。通过这些技术，在呼肠孤病毒核心蛋白中也检测到了新的锌结合和dsRNA结合活性。在小核糖核酸病毒蛋白酶的催化位点与σ3内的类转录因子IIIA锌结合位点之间观察到序列相似性。我们认为，σ3的锌结合和dsRNA结合活性可能对其对病毒和宿主细胞转录及翻译的调控作用至关重要。
