Studies on Escherichia coli chromosome proteins. II. DNA polymerases associated with the nucleoid.

Escherichia coli nucleoids isolated in the presence of spermidine have been shown to contain DNA polymerase activity of which more than 95% was ascribed to DNA polymerase I and the rest to DNA polymerases II and III. It also has been found that DNA polymerases II and III or DNA polymerase III substituted entirely for DNA polymerase I or DNA polymerase I and II in the nucleoids isolated from E. coli mutants lacking the corresponding enzyme activities.