VIRUS-SPECIFIC PROTEINS IN ESCHERICHIA COLI INFECTED WITH PHAGE QBETA

The synthesis of virus-specific proteins following infection of Escherichia coli with the RNA phage Qβ was studied using spheroplasts exposed to low concentrations of actinomycin D or rifampicin in the presence of an amino acid mixture containing radioactive leucine or histidine. Fractionation of the phage-induced proteins by acrylamide-gel electrophoresis revealed the presence of four peaks (I, IIa, IIb and III). Peak III contains neither histidine nor tryptophan and is identified as Qβ coat. Besides coat protein, Qβ particles have two more components, with the electrophoretic mobility of Peaks IIa and IIb, the nature of which is unknown, although presumably one or both of them correspond to attachment proteins. © 1969.