Identification of conserved slow codons that are important for protein expression and function.

Area of Science:

• Molecular Biology
• Genetics
• Biophysics

Background:

• The genetic code's redundancy allows multiple codons for one amino acid, leading to codon usage bias in organisms.
• Traditionally, preferred codons were linked to faster translation, while non-preferred codons were associated with slower rates.

Purpose of the Study:

• To investigate the role of non-preferred, 'slow' codons in co-translational protein folding and production.
• To identify specific locations where slow codons are functionally important and conserved across species.

Main Methods:

• Genome-wide analysis of homologous gene groups in divergent bacteria.
• Experimental generation of mutants by substituting conserved slow codons with fast codons.
• Cellular and biochemical assays to assess protein expression, folding, aggregation, and function.

Main Results:

• Identified conserved regions with bias towards slow codons across bacterial species.
• Slow-to-fast codon substitutions at specific locations reduced protein expression.
• These substitutions also increased protein aggregation and impaired protein function.

Conclusions:

• Slow codons have specific roles beyond translation speed, particularly in regulating co-translational protein folding.
• Conserved slow codons are critical for efficient protein production, proper folding, and overall protein function.
• The study provides a method to identify functionally relevant slow codon regions.