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20 Amino
acids, their single-letter data-base codes (SLC), and their
corresponding DNA codons
|
|
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. |
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