Bacteriophage PRD1

Bacteriophage PRD1, like the other Tectiviridae, has an inflexible icosahedral protein structure surrounding a lipid membrane. The linear dsDNA is contained inside this lipid-protein vesicle. The phage has a molecular mass of about 66x106 Da; by weight it is 15% DNA, 15% lipid, and the remaining weight is due to protein content. About half of the flexible inner membrane is made of host lipids; the rest of the vesicle consists of viral proteins. Cryo-electron microscopic reconstructions of PRD1 show the phage capsid is about 65.5 nm, measured as the diameter between two parallel edges, with a maximum diameter of 69.8nm when measured between vertices.