Re-examining Correlations Between Synonymous Codon Usage and Protein Bond Angles in Escherichia coli

Area of Science:

• Molecular Biology
• Bioinformatics
• Genetics

Background:

• Recent work suggested a link between synonymous codon usage and amino acid dihedral bond angles.
• This prior analysis did not account for gene expression, a major factor influencing codon usage.

Purpose of the Study:

• To re-examine the relationship between codon usage and amino acid dihedral bond angles.
• To investigate the impact of gene expression, mutation bias, and selection on this correlation.

Main Methods:

• Applied Rosenberg et al.'s approach to simulated protein-coding sequences.
• Simulations included random codon usage, mutation bias, and selection-mutation-drift equilibrium.
• Analyzed correlations between dihedral bond angles and codon usage in real and simulated sequences.

Main Results:

• Correlations between dihedral bond angle and codon usage were observed even with random codon usage, suggesting potential noise.
• Simulated sequences under selection-mutation-drift equilibrium showed strong agreement (91%) with real sequence analysis.
• This indicates that mutation bias, selection for translation efficiency, and gene expression interplay to drive the observed correlations.

Conclusions:

• The correlation between codon usage and dihedral bond angles is likely an artifact of varying codon usage across genes.
• Factors like mutation bias, natural selection, and gene expression must be controlled for when identifying novel codon usage patterns.
• This study highlights the importance of considering multi-factorial influences in molecular sequence analysis.