Supercoiled filaments propel them all.

Area of Science:

• Microbiology
• Structural Biology
• Evolutionary Biology

Background:

• Prokaryotic organisms like bacteria and archaea utilize motility machines for locomotion.
• Understanding the structural basis of these machines is crucial for deciphering microbial movement and evolution.
• Previous studies have focused on individual systems, lacking a comparative structural analysis.

Purpose of the Study:

• To determine the near-atomic-resolution structures of supercoiled filaments from both bacterial and archaeal motility machines.
• To investigate shared structural features despite a lack of sequence homology.
• To provide insights into the evolutionary convergence of prokaryotic locomotion.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was employed to obtain high-resolution structural data.
• Comparative structural analysis was performed on the obtained filament structures.
• Bioinformatic tools were used to assess homology and evolutionary relationships.

Main Results:

• Near-atomic-resolution cryo-EM structures of supercoiled filaments from bacterial and archaeal motility machines were determined.
• Shared fundamental structural features were identified in the filaments, despite no significant homology between the bacterial and archaeal proteins.
• The findings highlight a common architectural principle underlying prokaryotic locomotion.

Conclusions:

• The study reveals convergent evolution in the structural organization of bacterial and archaeal motility filaments.
• These findings underscore shared functional requirements driving the evolution of locomotion in prokaryotes.
• The high-resolution structures provide a foundation for future research into the mechanics and regulation of microbial motility.