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

Area of Science:

• Microbiology
• Structural Biology
• Biochemistry

Background:

• Staphylococcus aureus utilizes hibernation promoting factor (SaHPF) to form 100S ribosome dimers.
• This process conserves bacterial energy under stressful environmental conditions.
• Ribosome dimer formation is critically dependent on the dimerization of the SaHPF C-terminal domain (CTD^SaHPF).

Purpose of the Study:

• To elucidate the crystal structure of CTD^SaHPF.
• To identify key residues at the dimer interface of SaHPF.
• To investigate the role of these residues in SaHPF-mediated ribosome dimerization.

Main Methods:

• X-ray crystallography was used to determine the structure of CTD^SaHPF at 1.6 Å resolution.
• Site-directed mutagenesis was employed to alter specific residues within the SaHPF dimer interface.
• In vitro assays were performed using isolated S. aureus ribosomes to assess the impact of mutations on 100S dimer formation.

Main Results:

• The crystal structure revealed a precise arrangement of the CTD^SaHPF dimer interface.
• Mutagenesis analysis identified specific residues (Phe¹⁶⁰, Val¹⁶², Ile¹⁷³, Tyr¹⁷⁵, Ile¹⁸⁵) critical for SaHPF dimerization.
• Substitution of these identified residues abolished the formation of 100S ribosome dimers in vitro.

Conclusions:

• The C-terminal domain of SaHPF plays a crucial role in mediating 100S ribosome dimer formation.
• Specific amino acid residues within the SaHPF dimer interface are essential for this process.
• Understanding these interactions provides insights into bacterial survival mechanisms and potential therapeutic targets.