JBC, Vol. 252, Issue 4, 1148-1155, Feb, 1977
Inhibition of DNA replication in Escherichia coli by dibromophenol and other uncouplers
P. H. Weigel and P. T. Englund
DNA replication in Escherichia coli is inhibited by uncouplers such as
2,4-dibromophenol and 3,3'4',5-tetrachlorosalicylanilide. Inhibition occurs
in either aerobically or anaerobically growing cells or in cells made
permeable by toluene. With anaerobically growing cells, inhibition by
dibromophenol is reversible and occurs under conditions in which there is
no change in pools of ATP or deoxynucleoside triphosphates. With toluenized
cells, inhibition is not due to breakdown of deoxynucleoside triphosphates.
The rates of protein and RNA synthesis are not inhibited either in vivo or
in toluenized cells by concentrations of dibromophenol or
tetrachlorosalicylanilide which inhibit replication. It is generally
believed that uncouplers inhibit many other cellular processes by
collapsing a proton gradient across a membrane. However, the relative
effectiveness of eight uncouplers and related compounds to inhibit
replication did not parallel their ability to transport protons into E.
coli cells. Therefore, the inhibition by uncouplers does not suggest that
replication depends on a chemiosmotic process. A possible explanation for
the uncoupler sensitivity is provided by the finding that many of the
purified enzymes tested, including DNA polymerases II and III, are
inhibited by dibromophenol and tetrachlorosalicylanilide.