Transfer RNA

∞ generated and posted on 2016.08.28 ∞

Nucleic acid polymer that is responsible for carrying specific amino acids to ribosomes as well as complementarily interacting with codons.

Transfer RNAs have four aspects: (1) their anticodon, (2) where they bind amino acids, (3) how they interact with aminoacyl tRNA synthetases, and (4) how they interact with ribosomes. Transfer RNAs otherwise are relatively small RNA molecules, generally less than 100 nucleotides in length (by way of comparison, an mRNA of less than 100 nucleotides at best could in encode a polypeptide consisting of less than approximately 30 amino acids).

Transfer RNAs are free-floating within the cytoplasm except when they are interacting with ribosomes or aminoacyl tRNA synthetases. At least one transfer RNA must exist for every amino acid and up to one transfer RNA per sense codon in principle could exist. That number tends to be smaller (that is, >61), however, due to a property of transfer RNAs known as wobble.

See also tRNA and aminoacyl tRNA as well as ribosomal RNA (rRNA) and messenger RNA (mRNA).

Organisms tend to have biases in terms of the numbers of different types of tRNAs that they produce. These biases, in turn, lead to biases in codon usage, that is, where codons that are read by less abundant tRNAs tend to be replaced with codons that are read by more abundant tRNAs so as to increase the efficiency of ribosome usage during translation.