Dimerization of long hibernation promoting factor from Staphylococcus aureus: Structural analysis and biochemical characterization

Staphylococcus aureus hibernation promoting factor (SaHPF) is responsible for the formation of 100S ribosome dimers, which in turn help this pathogen to reduce energy spent under unfavorable conditions. Ribosome dimer formation strongly depends on the dimerization of the C-terminal domain of SaHPF (CTD^SaHPF). In this study, we solved the crystal structure of CTD^SaHPF at 1.6 Å resolution and obtained a precise arrangement of the dimer interface. Residues Phe¹⁶⁰, Val¹⁶², Thr¹⁷¹, Ile¹⁷³, Tyr¹⁷⁵, Ile¹⁸⁵ andThr¹⁸⁷ in the dimer interface of SaHPF protein were mutated and the effects were analyzed for the formation of 100S disomes of ribosomes isolated from S. aureus. It was shown that substitution of any of single residues Phe¹⁶⁰, Val¹⁶², Ile¹⁷³, Tyr¹⁷⁵ and Ile¹⁸⁵ in the SaHPF homodimer interface abolished the ribosome dimerization in vitro.