DNA replication in vitro starting with an intact phiX174 phage.

Conversion of the single-stranded DNA in the intact phiX174 phage particle to the duplex replicative form (RF) has been demonstrated in lysates form phage-sensitive cells. The conversion is resistant to rifampicin and requires participation of both a "membrane" fraction of the lysate and a multienzyme replicative system. The lipopolysaccharide phage receptor, while essential, does not replace the membrane fraction. Clear, nonsedimentable extract fractions prepared with a certain nonionic detergent can replace the membrane fraction. Purification of the activity in these extracts by adsorption to polypropylene film yields a fraction with a 5-fold increase in activity relative to lipopolysaccharide and 50-fold increase relative to protein. The low buoyant density (1.03 g/cm3) suggests a high phospholipid or detergent content in this fraction.