Mukai R, Hamatake R K, Hayashi M
Proc Natl Acad Sci U S A. 1979 Oct;76(10):4877-81. doi: 10.1073/pnas.76.10.4877.
The morphogenesis of bacteriophage phi X174 has been investigated by using an in vitro DNA synthesizing system. An extract of a B-mutant-infected cell is capable of synthesizing infectious phage in vitro when the B gene function is provided by the addition of an ammonium sulfate fraction of a C-mutant-infected-cell extract. This fraction contains the omega complex, a complex of phage-coded proteins with S = 108; the B-mutant extract does not. The purified omega complex, isolated from the C-mutant extract, caused the synthesis and encapsidation of viral DNA when added to B-mutant extract. The omega complex contains the B protein but it is the intact omega complex that functioned in the in vitro complementation of the B-mutant extract because other fractions containing B protein but no omega complex had little or no complementing activity. The results indicate that the omega complex is the phi X174 prohead. The B protein is not found in either the 132S or 114S phage particles but is an essential component of the prohead. This suggests that it may have a scaffolding function.
通过使用体外DNA合成系统研究了噬菌体φX174的形态发生。当通过添加C突变体感染细胞提取物的硫酸铵级分来提供B基因功能时，B突变体感染细胞的提取物能够在体外合成有感染性的噬菌体。该级分含有ω复合物，一种噬菌体编码的蛋白质复合物，沉降系数S = 108；B突变体提取物中没有。从C突变体提取物中分离出的纯化ω复合物，添加到B突变体提取物中时可导致病毒DNA的合成和衣壳化。ω复合物含有B蛋白，但发挥B突变体提取物体外互补作用的是完整的ω复合物，因为其他含有B蛋白但没有ω复合物的级分几乎没有或没有互补活性。结果表明ω复合物是φX174原头部。在132S或114S噬菌体颗粒中均未发现B蛋白，但它是原头部的必需成分。这表明它可能具有支架功能。
