Novel archaeal ribosome dimerization factor facilitating unique 30S-30S dimerization

Area of Science:

• Structural biology
• Molecular biology
• Biochemistry

Background:

• Protein synthesis is resource-intensive, necessitating regulation under stress.
• Ribosome inactivation involves proteins that mediate dimerization or prevent subunit association.
• Mechanisms of ribosome dimerization/anti-association in archaea are poorly understood.

Purpose of the Study:

• To elucidate the structural basis of ribosome dimerization and anti-association in archaea.
• To characterize the archaeal ribosome dimerization factor (aRDF) from Pyrococcus furiosus.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was used to determine the structure of the 30S dimer complex.
• Structural analysis of the aRDF-30S subunit interaction.

Main Results:

• The cryo-EM structure of an archaeal 30S dimer complexed with aRDF was resolved at 3.2 Å.
• aRDF homodimers stabilize two 30S subunits in a unique head-to-body architecture.
• aRDF directly interacts with ribosomal protein eS32, inhibiting 70S ribosome assembly.

Conclusions:

• The identified aRDF possesses anti-association properties, preventing 70S ribosome formation in archaea.
• This mechanism differs from bacterial and eukaryotic hibernation structures.
• The findings provide insights into archaeal stress adaptation and ribosome regulation.