Energy-dependent degradation of λO protein in Escherichia coli

Protein O of bacteriophage λ is a short-lived protein which has a key role in the replication of the phage DNA in Escherichia coli. Here we present evidence that λO degradation is energy dependent: it is impaired by cyanide and α-methylglucoside, both of which inhibit cellular energy metabolism. Removal of these inhibitors restored the degradation of λO. Our experiments suggest that limited amounts of cellular energy are sufficient to support λO degradation. In addition, degradation of λO protein is prevented by a mutation in the E. coli clpP gene, but not by a mutation in the clpA gene. These results suggest that the ClpP protease is involved in the energy- dependent degradation of the λO protein.