Vertebrate mitochondrial code

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

Evolution

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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

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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

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Amino acids biochemical properties nonpolar polar basic acidic Termination: stop codon
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
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

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DNA codons RNA codons This code (2) Standard code (1)
AGA AGA STOP = Ter (*) Arg (R)
AGG AGG STOP = Ter (*) Arg (R)
ATA AUA Met (M) Ile (I)
TGA UGA Trp (W) STOP = Ter (*)

Alternative initiation codons

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See also

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References

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  • This article contains public domain text from the NCBI page compiled by Andrzej Elzanowski and Jim Ostell.[9]
  1. ^ S. Osawa, T. Ohama, T. H. Jukes and K. Watanabe (September 1989). "Evolution of the mitochondrial genetic code. I. Origin of AGR serine and stop codons in metazoan mitochondria". J Mol Evol. 29 (3): 202–7. Bibcode:1989JMolE..29..202O. doi:10.1007/bf02100203. PMID 2506356. S2CID 21051869.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ R J Temperley; R Richter; S Dennerlein; R N Lightowlers; Z M Chrzanowska-Lightowlers (January 2010). "Hungry codons promote frameshifting in human mitochondrial ribosomes". Science. 327 (5963): 301. Bibcode:2010Sci...327..301T. doi:10.1126/science.1180674. PMID 20075246. S2CID 206522983.
  3. ^ Temperley, R. J.; Wydro, M; Lightowlers, R. N.; Chrzanowska-Lightowlers, Z. M. (2010). "Human mitochondrial mRNAs--like members of all families, similar but different". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1797 (6–7): 1081–5. doi:10.1016/j.bbabio.2010.02.036. PMC 3003153. PMID 20211597.
  4. ^ W. R. Hou, Y. Chen, X. Wu, J. C. Hu, Z. S. Peng, J. Yang, Z. X. Tang, C. Q. Zhou, Y. M. Li, S. K. Yang, Y. J. Du, L. L. Kong, Z. L. Ren, H. Y. Zhang and S. S. Shuai (December 2006). "A complete mitochondrial genome sequence of Asian black bear Sichuan subspecies (Ursus thibetanus mupinensis)". Int J Biol Sci. 3 (2): 85–90. doi:10.7150/ijbs.3.85. PMC 1752227. PMID 17205108.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ Oh, D. J.; Kim, J. Y.; Lee, J. A.; Yoon, W. J.; Park, S. Y.; Jung, Y. H. (2007). "Complete mitochondrial genome of the rabbitfish Siganus fuscescens (Perciformes, Siganidae)". DNA Sequence. 18 (4): 295–301. doi:10.1080/10425170701248525. PMID 17541835. S2CID 38458668.
  6. ^ Ki, J. S.; Hwang, D. S.; Park, T. J.; Han, S. H.; Lee, J. S. (2009). "A comparative analysis of the complete mitochondrial genome of the Eurasian otter Lutra lutra (Carnivora; Mustelidae)". Molecular Biology Reports. 37 (4): 1943–55. doi:10.1007/s11033-009-9641-0. PMID 19757186. S2CID 24233602.
  7. ^ Nakamoto T (March 2009). "Evolution and the universality of the mechanism of initiation of protein synthesis". Gene. 432 (1–2): 1–6. doi:10.1016/j.gene.2008.11.001. PMID 19056476.
  8. ^ P. Desjardins & R. Morais (February 1991). "Nucleotide sequence and evolution of coding and noncoding regions of a quail mitochondrial genome". J Mol Evol. 32 (2): 153–161. Bibcode:1991JMolE..32..153D. doi:10.1007/bf02515387. PMID 1706782. S2CID 1974138.
  9. ^ The Genetic Codes