Vertebrate mitochondrial code

Alternative genetic code From Wikipedia, the free encyclopedia

The vertebrate mitochondrial code (translation table 2) is the genetic code found in the mitochondria of all vertebrata.

Evolution

AGA and AGG were thought to have become mitochondrial stop codons early in vertebrate evolution.[1] However, at least in humans it has now been shown that AGA and AGG sequences are not recognized as termination codons. A -1 mitoribosome frameshift occurs at the AGA and AGG codons predicted to terminate the CO1 and ND6 open reading frames (ORFs), and consequently both ORFs terminate in the standard UAG codon.[2]

Incomplete stop codons

Mitochondrial genes in some vertebrates (including humans) have incomplete stop codons ending in U or UA, which become complete termination codons (UAA) upon subsequent polyadenylation.[3][4][5][6]

Translation table

Amino acids biochemical properties nonpolar polar basic acidic Termination: stop codon
More information 1st base, 2nd base ...
Mitochondrial genetic code
1st
base
2nd base 3rd
base
U C A G
U UUU (Phe/F) Phenylalanine UCU (Ser/S) Serine UAU (Tyr/Y) Tyrosine UGU (Cys/C) Cysteine U
UUC UCC UAC UGC C
UUA (Leu/L) Leucine UCA UAA Stop UGA (Trp/W) Tryptophan     A
UUG UCG UAG UGG G
C CUU CCU (Pro/P) Proline CAU (His/H) Histidine CGU (Arg/R) Arginine U
CUC CCC CAC CGC C
CUA CCA CAA (Gln/Q) Glutamine CGA A
CUG CCG CAG CGG G
A AUU (Ile/I) Isoleucine ACU (Thr/T) Threonine         AAU (Asn/N) Asparagine AGU (Ser/S) Serine U
AUC ACC AAC AGC C
AUA (Met/M) Methionine ACA AAA (Lys/K) Lysine AGA Stop A
AUG[A] ACG AAG AGG G
G GUU (Val/V) Valine GCU (Ala/A) Alanine GAU (Asp/D) Aspartic acid GGU (Gly/G) Glycine U
GUC GCC GAC GGC C
GUA GCA GAA (Glu/E) Glutamic acid GGA A
GUG GCG GAG GGG G
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A The codon AUG both codes for methionine and serves as an initiation site: the first AUG in an mRNA's coding region is where translation into protein begins.[7]

Differences from the standard code

More information DNA codons, RNA codons ...
DNA codonsRNA codonsThis code (2)Standard code (1)
AGAAGASTOP = Ter (*)Arg (R)
AGGAGGSTOP = Ter (*)Arg (R)
ATAAUAMet (M)Ile (I)
TGAUGATrp (W)STOP = Ter (*)
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Alternative initiation codons

See also

References

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