title: Isolation and identification of bacteriophage phi X174 prohead.
abstract: 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.
mesh_terms: D010584:Bacteriophage phi X 174 / Q000378:metabolism*; D004279:DNA, Viral / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D005816:Genetic Complementation Test; D007700:Kinetics; D008970:Molecular Weight; D014764:Viral Proteins / Q000096:biosynthesis; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins