KuljetusRNA

KuljetusRNA, also known as transfer RNA or tRNA, is a crucial molecule in the process of protein synthesis within living cells. It acts as an adapter, bridging the gap between the genetic code carried by messenger RNA (mRNA) and the amino acids that are assembled into proteins. Each tRNA molecule has a specific structure that allows it to bind to a particular amino acid and also to recognize a corresponding three-nucleotide sequence on the mRNA, called a codon.

The structure of tRNA is often depicted as a cloverleaf in two dimensions, but it folds into a more complex L-shape in three dimensions. Key regions include the acceptor stem, where the amino acid attaches, and the anticodon loop, which contains the anticodon that pairs with the mRNA codon. This pairing is based on complementary base pairing rules.

During translation, ribosomes move along the mRNA molecule. As each codon is exposed, a tRNA molecule with the matching anticodon arrives, carrying its specific amino acid. The ribosome then catalyzes the formation of a peptide bond between this new amino acid and the growing polypeptide chain. This process continues until a stop codon is encountered on the mRNA, signaling the completion of the protein. Without tRNA, the genetic information encoded in DNA and transcribed into mRNA could not be accurately translated into the functional proteins that carry out virtually all cellular activities.