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20 Amino acids, their single-letter data-base codes (SLC), and their corresponding DNA codons |
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Amino Acid |
SLC |
DNA codons |
|
Isoleucine |
I |
ATT, ATC, ATA |
| Leucine |
L |
CTT, CTC, CTA, CTG, TTA, TTG |
| Valine |
V |
GTT, GTC, GTA, GTG |
| Phenylalanine |
F |
TTT, TTC |
| Methionine | M | ATG |
| Cysteine | C |
TGT, TGC |
| Alanine |
A |
GCT, GCC, GCA, GCG |
| Glycine |
G |
GGT, GGC, GGA, GGG |
| Proline |
P |
CCT, CCC, CCA, CCG |
| Threonine |
T |
ACT, ACC, ACA, ACG |
| Serine | S | TCT, TCC, TCA, TCG, AGT, AGC |
|
Tyrosine |
Y | TAT, TAC |
| Tryptophan | W | TGG |
| Glutamine | Q | CAA, CAG |
| Asparagine | N | AAT, AAC |
| Histidine |
H |
CAT, CAC |
| Glutamic acid |
E |
GAA, GAG |
|
Aspartic acid |
D |
GAT, GAC |
| Lysine |
K |
AAA, AAG |
| Arginine |
R |
CGT, CGC, CGA, CGG, AGA, AGG |
| Stop codons | Stop | TAA, TAG, TGA |
| In this table, the twenty amino acids found in proteins are listed, along with the single-letter code used to represent these amino acids in protein data bases. The DNA codons representing each amino acid are also listed. All 64 possible 3-letter combinations of the DNA coding units T, C, A and G are used either to encode one of these amino acids or as one of the three stop codons that signals the end of a sequence. While DNA can be decoded unambiguously, it is not possible to predict a DNA sequence from its protein sequence. Because most amino acids have multiple codons, a number of possible DNA sequences might represent the same protein sequence. | ||