Early replicative intermediates of Escherichia coli chromosome isolated from a membrane complex.
The replication origin region of the Escherichia coli chromosome was isolated from an outer membrane fraction. The chromosome was further purified by centrifugation in a cesium chloride gradient. Early replicative intermediates were enriched in the preparation when cytosine-1-beta-arabinofuranoside was added to the culture at the time of initiation of chromosome replication. DNA fragments with an eye structure having two branches of less than 400-500 bp in length were associated with components that were removed by phenol treatment. We conclude that the replication fork usually proceeds counter-clockwise toward the unc operon in the earliest period of replication.
D001482:Base Composition; D002462:Cell Membrane / Q000502:physiology; D002876:Chromosomes, Bacterial / Q000502:physiology* / Q000648:ultrastructure; D003561:Cytarabine / Q000494:pharmacology; D004261:DNA Replication; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D008854:Microscopy, Electron
D003561:Cytarabine