Phenotypes of dnaA mutants of escherichia coli sensitive to detergents and organic solvents

We examined growth sensitivities of dnaA mutants of Escherichia coli to detergents (deoxycholic acid, cholic acid) and organic solvents (ethanol, glycerol). The dnaA602, dnaA604, dnaA5, and dnaA46 mutants with mutations in the putative ATP binding site of DnaA protein showed higher sensitivities to the detergents than did the wild-type strain. The dnaA508 and dnaA167 mutants with mutations in the N-terminal region of DnaA protein, however, showed higher sensitivities to organic solvents. The dnaA204 and dnaA205 mutants with a mutation in the C-terminal region of DnaA protein showed similar sensitivity as did the wild-type strain to reagents. Complementation analysis with a plasmid carrying the wild-type dnaA gene confirmed that dnaA mutations are responsible for these phenotypes that are sensitive to the reagents.