How Hibernation Factors RMF, HPF, and YfiA Turn Off Protein Synthesis

Abstract

The Hibernating Ribosome When bacteria enter stationary phase, their ribosomes are inactivated. In Escherichia coli , ribosome modulation factor (RMF) causes dimerization of the 70S ribosome and the dimer is stabilized by, hibernation promotion factor (HPF). Alternately, the stationary phase protein, YfiA, inactivates 70S ribosomes. Polikanov et al. (p. 915 ) present high-resolution structures of the Thermus thermophilus 70S ribosome bound to each of these three factors. The structures suggest that RMF binding inhibits protein synthesis by preventing initial messenger RNA (mRNA) binding and that HPF and YfiA have overlapping binding sites and would both interfere with binding of mRNA, transfer RNA, and initiation factors.