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Overview


The translation of mRNA into protein is critical for expression of genetic information.

The genetic code, deciphered in the 1960's and 1970's, specifies nucleotide triplets (or codons) corresponding to individual amino acid residues. A set of adapter molecules enable this correspondence between the amino acid and its codon(s) - these molecules are transfer RNAs (tRNA). An enzyme, termed an aminoacyl-tRNA synthetase, makes the connection between each tRNA and the corresponding amino acid. Each tRNA encodes a nucleotide sequence, the anti-codon, complementary to a codon for that particular amino acid. The complement of tRNAs in a cell have been described as representing a "molecular dictionary" in that they define the relationships between words in the nucleic acid language and words in the polypeptide language.

Translation requires these amino acid-charged tRNAs to brought into immediate proximity to the mRNA, matching the codon and anti-codon sequences and allowing the polymerisation of amino acid residues in the correct sequence. This is achieved by the ribosome, a complex of RNA and proteins. This complex binds mRNA and "reads" it - accepting charged tRNAs in the order specified by the message and consequently transferring their amino acid residues to the polypeptide chain in the correct order. The mRNA is "read" by the ribosome from 5' to 3' with the encoded polypeptide translated from its N-terminal residue.


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[VSNS-PPS Index] Garry Myers
garry@menzies.su.edu.au