Protein folding information in nucleic acids which is not present in the genetic code

Area of Science:

• Molecular Biology
• Bioinformatics
• Structural Biology

Background:

• Messenger RNA (mRNA) secondary structures play crucial roles in gene regulation and protein synthesis.
• The relationship between mRNA sequence, its folding energy, and the resulting protein structure is an area of active research.

Purpose of the Study:

• To investigate the correlation between codon positions, mRNA free folding energy (FFE), and protein structure.
• To determine if periodic patterns in mRNA folding energy relate to protein residue co-localization.

Main Methods:

• Analysis of free folding energy (FFE) in different codon residue subsequences of mRNAs.
• Comparison of FFE patterns in coding regions (exons) versus non-coding regions (introns).
• Correlation analysis between RNA folding energy dot plots and protein residue contact maps using 81 protein structures.

Main Results:

• Nucleic acid subsequences at the 1st and/or 3rd codon positions exhibit significantly higher FFE than those at the 2nd position (P < 0.0001).
• This periodic FFE difference is specific to coding sequences and absent in introns.
• Additive FFE in the 1st and 3rd positions suggests complementary base pairing and selection for local mRNA secondary structures.
• Similarities observed between RNA folding energy dot plots and protein residue contact maps.
• Amino acids coded by partially reverse and complementary codons are preferentially co-located in protein structures.

Conclusions:

• Codon position-dependent mRNA secondary structures are linked to the formation of specific protein structures.
• The study reveals a direct connection between the structural properties of mRNA and the spatial arrangement of amino acids in proteins.
• These findings highlight a novel layer of gene expression regulation mediated by mRNA structure and its influence on protein architecture.