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Compositional biases and polyalanine runs in humans.
Julie Cocquet1, Elfride De Baere, Sandrine Caburet
1INSERM E0021 and U361, Reproduction et Physiopathologie Obstétricale, Hôpital Cochin, 75014 Paris, France.
Genetics
|December 12, 2003
Summary
Human proteins with polyalanine tracts show specific amino acid patterns and biased codon usage in their open reading frames (ORFs). This compositional bias is strongly linked to the GC content of the third codon base, indicating evolutionary ORF selection.
Area of Science:
- Molecular Biology
- Genomics
- Protein Science
Background:
- Human proteins can contain polyalanine tracts, which are repetitive sequences of alanine amino acids.
- The open reading frames (ORFs) encoding these proteins often exhibit non-random codon usage patterns.
Purpose of the Study:
- To investigate the relationship between amino acid composition and codon usage bias in human proteins with polyalanine tracts.
- To explore the potential role of open reading frame (ORF) evolution in shaping protein composition.
Main Methods:
- Analysis of human protein sequences for polyalanine tracts.
- Examination of codon usage patterns within the ORFs of these proteins.
- Correlation analysis between amino acid content and GC content at the third codon position.
Main Results:
- Proteins with polyalanine tracts frequently display runs of other amino acids.
- A significant correlation was observed between the content of alanine, glycine, proline, and histidine and the GC content of the third codon base.
- This suggests that ORF evolution influences the compositional specificity of these proteins.
Conclusions:
- The compositional characteristics of human proteins with polyalanine tracts are significantly influenced by the evolutionary pressures on their encoding ORFs.
- Codon usage bias, particularly related to GC content, plays a key role in the observed amino acid patterns.