The 'DNA-membrane complex' of Escherichia coli B/r. Its composition and properties and the fate of nascent and genome DNA during DNA synthesis.

The composition and properties of 'DNA-membrane complex' of Escherichia coli B/r have been investigated. The 'complexes' contain most of the DNA and membrane of the cells, and about 50% and 25% of the RNA and protein respectively. The properties of DNA synthesized by the 'complexes' are described and the process is concluded to be largely mediated through polymerase I. Nascent DNA synthesized by the 'DNA-membrane complexes' was of two main classes, one of molecular weight around 600,000--800,000 and the other of higher molecular weight. Polynucleotide ligase activity was not detectable. The onset of synthesis coincided with the dissociation of at least 70% of the genome DNA and all of the nascent DNA from the 'complexes' and was concomitant with the action of a nuclease on parental DNA. This nuclease activity was not ATP-dependent.