Biology:Vertebrate mitochondrial code
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Short description: An alternative genetic code found in the mitochondrial genome of vertebrates
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 |
| 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
| 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
See also
References
- This article contains public domain text from the NCBI page compiled by Andrzej Elzanowski and Jim Ostell.[9]
- ↑ 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. doi:10.1007/bf02100203. PMID 2506356. Bibcode: 1989JMolE..29..202O.
- ↑ 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. doi:10.1126/science.1180674. PMID 20075246. Bibcode: 2010Sci...327..301T.
- ↑ 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. PMID 20211597.
- ↑ 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. PMID 17205108.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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. doi:10.1007/bf02515387. PMID 1706782. Bibcode: 1991JMolE..32..153D.
- ↑ The Genetic Codes
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