Aminoacyl-tRNA synthetase classes and groups in prokaryotes

Area of Science:

• Evolutionary biology
• Molecular biology
• Origin of life studies

Background:

• Aminoacyl-tRNA synthetases (aaRS) are essential enzymes involved in protein synthesis.
• Understanding aaRS evolution is key to deciphering early life forms and their biochemical pathways.

Purpose of the Study:

• To investigate the evolutionary relationships and specificities of aminoacyl-tRNA synthetases in prokaryotes.
• To reconstruct ancestral sequences and phylogenetic trees to understand evolutionary trajectories.

Main Methods:

• Phylogenetic analysis using the Maximum Likelihood method.
• Reconstruction of ancestral sequences for aminoacyl-tRNA synthetases.
• Comparative analysis of protein segments (N-terminal and C-terminal) across different domains of prokaryotes.

Main Results:

• Class I aaRS N-terminal evolution was influenced by amino acid hydropathy in both prokaryotic domains.
• Class I aaRS C-terminal evolution differed between domains, linked to tRNA modification types.
• Class II aaRS in Archaea showed heterogeneity; in bacteria, a division into two groups (IIa and IIb) based on amino acid specificities was observed.

Conclusions:

• Diverse selective pressures acted on different protein regions of aminoacyl-tRNA synthetases.
• These varied forces led to complex phylogenetic patterns, providing insights into prokaryotic evolution.
• The findings contribute to a deeper understanding of the origins and early evolution of life.