Одна из проблем при экспрессии белков связана с редкими кодонами в кодирующей последовательности. В таблице приведены частоты встречаемости (на 1000) кодонов в генах различных организмов. Если бы распределение было равномерным, то частота для всех кодонов была бы в районе 16.4.
Представленные данные взяты из "Codon-Usage Database" содержащей 392,382 полных кодирующих последовательностей (CDS's) для 11,713 организмов. Об этой базе данных можно прочитать в статье "Codon usage tabulated from the international DNA sequence databases: status for the year 2000". Nakamura, Y., Gojobori, T. and Ikemura, T. (2000) Nucl. Acids Res. 28, 292.
О влиянии редких кодонов на экспрессию белков можно почитать в обзоре: "Effects of rare codon clusters on high-level expression of heterologous proteins in Escherichia coli" [Review article] James F Kane Current Opinion in Biotechnology 1995, 6:494-500.
HUM Homo sapiens
MUS Mus musculus
DRO Drosophila melanogaster
ATH Arabidopsis thaliana
YSC Saccharomyces cerevisiae
ECO Escherichia coli
Амино-
кислота | Кодон | Организм |
| HUM | MUS | DRO | ATH | YSC | ECO |
| Arg | CGA | 6.3 | 6.7 | 8.5 | 6.3 | 3.0 | 3.5 |
| CGC | 10.8 | 10.1 | 17.9 | 3.7 | 2.6 | 20.6 |
| CGG | 11.6 | 10.5 | 8.3 | 4.8 | 1.7 | 5.4 |
| CGU | 4.6 | 4.7 | 8.7 | 8.8 | 6.5 | 20.6 |
| AGA | 11.5 | 11.4 | 5.1 | 19.0 | 21.3 | 2.8 |
| AGG | 11.3 | 11.6 | 6.4 | 10.9 | 9.3 | 1.7 |
| Leu | CUA | 7.0 | 7.5 | 8.3 | 10.1 | 13.4 | 4.0 |
| CUC | 19.3 | 19.6 | 13.9 | 15.7 | 5.4 | 10.3 |
| CUG | 39.7 | 39.3 | 38.7 | 10.0 | 10.4 | 50.4 |
| CUU | 12.8 | 12.3 | 9.1 | 24.2 | 12.2 | 11.2 |
| UUA | 7.3 | 6.0 | 4.3 | 13.2 | 26.4 | 13.9 |
| UUG | 12.5 | 12.5 | 16.2 | 21.3 | 27.1 | 13.1 |
| Ser | UCA | 11.9 | 11.2 | 7.6 | 18.3 | 18.8 | 8.1 |
| UCC | 17.5 | 18.1 | 19.6 | 10.9 | 14.2 | 9.1 |
| UCG | 4.5 | 4.5 | 16.6 | 9.0 | 8.6 | 8.6 |
| UCU | 14.8 | 15.4 | 6.8 | 25.0 | 23.6 | 9.9 |
| AGC | 19.3 | 20.0 | 20.4 | 11.2 | 9.7 | 15.3 |
| AGU | 12.0 | 12.2 | 11.5 | 14.3 | 14.2 | 9.2 |
| Thr | ACA | 14.9 | 15.6 | 10.7 | 15.9 | 17.7 | 8.2 |
| ACC | 19.3 | 19.6 | 21.4 | 10.1 | 12.6 | 22.8 |
| ACG | 6.3 | 6.1 | 14.4 | 7.6 | 8.0 | 13.8 |
| ACU | 12.9 | 13.2 | 9.5 | 17.6 | 20.2 | 10.0 |
| Pro | CCA | 16.7 | 17.3 | 13.5 | 16.1 | 18.2 | 8.6 |
| CCC | 20.0 | 19.1 | 17.9 | 5.2 | 6.8 | 5.1 |
| CCG | 7.0 | 6.8 | 16.0 | 8.2 | 5.3 | 22.0 |
| CCU | 17.3 | 18.7 | 6.9 | 18.3 | 13.6 | 7.2 |
| Ala | GCA | 15.9 | 15.5 | 12.8 | 17.4 | 16.2 | 21.0 |
| GCC | 28.3 | 26.7 | 33.6 | 10.0 | 12.6 | 24.5 |
| GCG | 7.5 | 7.1 | 14.0 | 8.6 | 6.1 | 31.8 |
| GCU | 18.5 | 19.7 | 14.5 | 27.5 | 21.1 | 16.8 |
| Gly | GGA | 16.4 | 17.3 | 17.8 | 23.5 | 10.9 | 8.7 |
| GGC | 22.7 | 22.9 | 26.6 | 8.9 | 9.7 | 28.4 |
| GGG | 16.4 | 15.9 | 4.7 | 10.1 | 6.0 | 11.0 |
| GGU | 10.8 | 11.7 | 13.3 | 21.7 | 23.9 | 25.9 |
| Val | GUA | 7.0 | 6.9 | 6.3 | 10.2 | 11.8 | 11.4 |
| GUC | 14.6 | 15.6 | 13.9 | 12.5 | 11.6 | 14.6 |
| GUG | 28.8 | 29.0 | 28.1 | 17.3 | 10.7 | 25.2 |
| GUU | 10.9 | 10.1 | 10.9 | 27.2 | 22.0 | 19.6 |
| Lys | AAA | 24.0 | 21.3 | 16.5 | 31.3 | 42.1 | 34.8 |
| AAG | 32.6 | 34.6 | 39.5 | 32.5 | 30.8 | 11.5 |
| Asn | AAC | 19.8 | 21.5 | 26.1 | 20.7 | 24.9 | 21.8 |
| AAU | 17.0 | 15.5 | 20.8 | 23.1 | 36.0 | 19.2 |
| Gln | CAA | 12.0 | 11.6 | 15.6 | 19.7 | 27.5 | 14.7 |
| CAG | 34.5 | 34.5 | 36.8 | 15.0 | 12.2 | 28.6 |
| His | CAC | 14.9 | 15.3 | 16.2 | 8.6 | 7.8 | 9.6 |
| CAU | 10.5 | 9.9 | 10.6 | 14.1 | 13.7 | 12.6 |
| Glu | GAA | 29.1 | 26.9 | 20.9 | 35.0 | 45.9 | 39.7 |
| GAG | 40.2 | 40.3 | 43.0 | 32.1 | 19.1 | 18.2 |
| Asp | GAC | 26.1 | 27.5 | 24.7 | 17.1 | 20.3 | 19.5 |
| GAU | 22.4 | 21.4 | 27.6 | 37.2 | 37.8 | 32.6 |
| Tyr | UAC | 15.8 | 16.8 | 18.4 | 13.5 | 14.7 | 12.3 |
| UAU | 12.1 | 11.8 | 10.7 | 15.2 | 18.8 | 16.9 |
| Cys | UGC | 12.3 | 12.6 | 13.3 | 7.2 | 4.7 | 6.2 |
| UGU | 10.0 | 10.9 | 5.3 | 10.9 | 8.0 | 5.1 |
| Phe | UUC | 20.5 | 21.6 | 21.8 | 20.3 | 18.2 | 16.4 |
| UUU | 17.0 | 16.0 | 13.1 | 22.7 | 26.0 | 21.9 |
| Ile | AUA | 7.2 | 6.6 | 9.3 | 13.1 | 17.8 | 5.6 |
| AUC | 21.6 | 22.9 | 23.0 | 18.3 | 17.1 | 24.4 |
| AUU | 15.8 | 14.6 | 16.5 | 22.1 | 30.2 | 30.1 |
| Met | AUG | 22.3 | 22.2 | 23.5 | 24.4 | 20.9 | 26.8 |
| Trp | UGG | 12.9 | 12.9 | 9.9 | 12.6 | 10.3 | 13.9 |
| Ter | UAA (ochre) | 0.7 | 0.6 | 0.8 | 0.9 | 1.0 | 2.0 |
| UAG (amber) | 0.5 | 0.5 | 0.6 | 0.5 | 0.5 | 0.2 |
| UGA (opal) | 1.3 | 1.1 | 0.5 | 1.0 | 0.6 | 0.9 |
| Количество CDS's | 27143 | 11484 | 19565 | 33661 | 11644 | 10136 |
| Количество кодонов | 12816923 | 5545064 | 10281892 | 14647315 | 5624171 | 3178987 |
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