Global importance of RNA secondary structures in protein-coding sequences

Area of Science:

• Molecular Biology
• Genomics
• Bioinformatics

Background:

• Protein-coding sequences in messenger RNAs (mRNAs) serve as templates for protein translation.
• RNAs can adopt secondary structures through intramolecular base-pairing, influencing their function.

Purpose of the Study:

• To investigate the global nucleotide distribution bias within codons across all taxa.
• To determine the impact of RNA secondary structures on codon bias and protein-coding regions.

Main Methods:

• Analysis of nucleotide distribution within codons on a global scale.
• Identification and quantification of under-represented RNA secondary structure classes (e.g., class c1).

Main Results:

• A significant bias in nucleotide distribution within codons was observed across all life forms.
• RNA secondary structures requiring specific base-pairing (class c1) are under-represented in coding sequences.
• Codon position 2 appears to have a lesser impact on amino acid selection compared to codon position 1.

Conclusions:

• The observed codon bias may arise from the co-evolution of codon sequences and mRNA secondary structures.
• RNA secondary structures play a generally important role within the protein-coding regions of mRNAs.
• This suggests a functional significance of mRNA secondary structures beyond simple linear templating.