InterPro domain: IPR003489

This family consists of ribosome hibernation promoting factor (RHF). RHF promotes and stabilizes dimerization of 70S ribosomes by the ribosome modulation factor (RMF), leading to the formation of inactive 100S ribosomes during the stationary phase [ 1 ].

This family also includes RaiA ("ribosome-associated inhibitor A", also known as Protein Y (PY), YfiA, and SpotY). This is a stress-response protein that binds the ribosomal subunit interface and arrests translation by interfering with aminoacyl-tRNA binding to the ribosomal A site [ 2 ]. RaiA is also thought to counteract miscoding at the A site thus reducing translation errors [ 3 ]. The RaiA fold structurally resembles the double-stranded RNA-binding domain (dsRBD) [ 4 ].

1. Role of HPF (hibernation promoting factor) in translational activity in Escherichia coli. J. Biochem. 143, 425-33
2. Structural basis for the control of translation initiation during stress. Nat. Struct. Mol. Biol. 11, 1054-9
3. The ribosome-associated inhibitor A reduces translation errors. Biochem. Biophys. Res. Commun. 320, 354-8
4. Ribosome-associated factor Y adopts a fold resembling a double-stranded RNA binding domain scaffold. Eur. J. Biochem. 269, 5182-91