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Updated: Aug 12, 2026
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Residue-specific Incorporation of Noncanonical Amino Acids into Model Proteins Using an Escherichia coli Cell-free Transcription-translation System
Published on: August 1, 2016
Amino acid composition of proteins: Selection against the genetic code
Science (New York, N.Y.)
|June 4, 1975
Summary
Protein amino acid composition deviates from genetic code predictions. Key amino acids like lysine and aspartic acid are overrepresented, while others like arginine and serine are underrepresented, resulting in a neutral overall charge.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- The genetic code dictates the translation of codons into amino acids.
- Understanding the relationship between codon usage and protein composition is crucial for molecular biology.
Purpose of the Study:
- To compare the distribution of amino acids in representative proteins with their representation in the genetic code.
- To identify deviations and understand their implications for protein properties.
Main Methods:
- Analysis of amino acid frequencies in 68 representative proteins.
- Comparison with the distribution of 61 codons in the genetic code.
Main Results:
- Lysine, aspartic acid, glutamic acid, and alanine showed higher-than-expected frequencies.
- Arginine, serine, leucine, cysteine, proline, and histidine were found in lower-than-expected amounts.
- The combined codons for arginine/lysine (11.0%) and aspartic acid/glutamic acid (11.3%) suggest a roughly neutral average charge.
Conclusions:
- Significant differences exist between amino acid abundance in proteins and their genetic code representation.
- These deviations may influence protein structure and function.
- The balance of charged amino acids contributes to a neutral overall protein charge.
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