Structure and synthesis of a lipid-containing bacteriophage. Effects of lipids containing cis or trans fatty acids on the reconstitution of bacteriophage PM2.
Infectious PM2 virus paticles could be reconstituted in vitro from a mixture of nucleocapsid, phospholipids containing cis fatty acids, and proteins I and II. The presence or absence of acyl phosphatidylglycerol, a minor lipid component of thevirion, did not affect the reconstitution of infectious particles, even though it was incorporated into the particles when present. When phosphatidylglycerol was completely replaced by acyl phosphatidylglycerol in the reconstitution mixture, no infections particles were formed. Lipids containing either cis or trans fatty acids were also used for reconstitution in vitro of the lipid-containing bacteriophage PM2. Regardless of the ratio of phosphatidlyglycerol to phospatidylethanolamine in the reconstitution mixture, infectious particles were formed and had almost the same phospholipid composition when lipids containing cis-palmitoleic acid were used; no infectious particles were obtained when lipids containing trans-palmitoleic acid were used. In the latter case, virus-like particles were, however, formed. Reconstituted particles containing cis fatty acids were infectious when tested on wild type Pseudomonas BAL-31 as well as on the unsaturated fatty acid auxotroph grown in the presence of either cis or trans-palmitoleic acid. Reconstituted particles containing trans fatty acids were not infectious on any of these cells. When trans fatty acids as well as cis fatty acids were present in the reconstitution mixture, then there was a lower yield of infectious particles. Particles with either cis or trans fatty acids had all four viral proteins and adsorbed to BAL-31 host cells in a specific manner.