Rifampin inhibits the â subunit of the E. coli RNA polymerase. A typical rifR mutant contains a mutant gene that produces a â subunit that no longer binds rifampin. Propose one other genetic alteration by which an E. coli might become resistant to the drug rifampin (without mating with other bacteria) and the molecular basis for this other resistant phenotype. What is your evidence this other type doesn’t exist?

Question

Rifampin inhibits the â subunit of the E. coli RNA polymerase.  A typical rifR mutant contains a mutant gene that produces a â subunit that no longer binds rifampin.  Propose one other genetic alteration by which an E. coli might become resistant to the drug rifampin (without mating with other bacteria) and the molecular basis for this other resistant phenotype.  What is your evidence this other type doesn’t exist?