FIG 2.

The dimerization function of HPF is required for maintaining active ribosomes. Ribosomes were harvested from the wild type (JDB1772), a Δhpf strain (JDB4221), or a strain with a mutant HPF that can bind the ribosome but does not form ribosome dimers (hpfΔdimer strain [JDB4227]) grown to stationary phase. (A) Sucrose density gradients of ribosomes. Fractions collected from gradients were probed with a polyclonal antibody raised against HPF. (B) Western blot with quantification from independent experiments showing translational activity of ribosomes harvested from wild-type, Δhpf, and hpfΔdimer strains. Error bars represent standard deviation.