Kinetics and characterization of the proteins synthesized during infection by bacteriophage PM2

Using two-dimensional gel electrophoresis, we have examined the proteins whose synthesis is stimulated in Alteromonas espejiana by infection with the membrane-containing bacteriophage PM2. In addition to four virus structural proteins, 11 non-structural proteins have been resolved and identified by their apparent isoelectric points and molecular weights. The relative rate of synthesis of each of the proteins was determined during the course of infection. Synthesis of the earliest proteins began around 10 min after infection. Synthesis of the virus structural proteins as a group did not begin until about 25 min after infection. In contrast to these structural proteins, the rate of synthesis of most of the non-structural virus proteins began to decline between 30 and 35 min after infection. This time preceded the onset of cell lysis marked by ion leakage (47 min); it corresponded to the beginning of packaging of virus DNA, removing that DNA from replication and transcription. Protein processing could not be demonstrated by pulse-chase labelling. These 15 proteins account for all of the coding capacity of the virus DNA. The virus origin of 14 of these proteins was established in an in vitro transcription-translation system programmed by PM2 DNA.