Translation (genetics)

Article

July 1, 2022

Translation is the second step in the process of protein synthesis, which is also part of the overall process of gene expression. In translation, informative RNA (i-RNA) is decoded to produce a specific polypeptide based on rules that specify the genetic code. Translations must always be preceded by transcription. Similar to transcription, translation takes place in three phases: initiation elongation termination The property of some antibiotics, as well as their power, is to influence the translation process by either interfering with it or completely terminating it. Antibiotics that act on this principle are anisomycin, cycloheximide, chloramphenicol and tetracycline.

Basic mechanism

Informative RNA (i-RNA) is a molecule that carries a message, or a genetic code, that is, a genetic code from chromosome to ribosome. The genetic information that i-RNA carries through hydrogen bonds is identified and linked to specific transport RNAs, or t-RNAs, which transfer specific amino acids to the growing polynucleotide chain at the site of ribosomal protein synthesis. Genetic information is transmitted in a group of three units, ie three nucleotides. Each of these three nucleotide groups represents one amino acid. Each of the three i-RNA nucleotides is called a codon, and their three complementary t-RNA nucleotides are called anti-codons. Aminoacyl t-RNA synthetase is an enzyme that controls the binding of precisely defined amino acids to the corresponding t-RNA to form aminoacyl-t-RNA. Prokaryotic translation Prokaryotes do not have a nucleus, so mRNA translation takes place at the same time as transcription. Due to this simultaneous activity, translation is said to be polyribosomal because more than one ribosome is active.

Initiation

Translation initiation requires the presence of a small ribosomal unit that binds to the start codon on the i-RNA, which in turn indicates where the i-RNA begins to encode a particular protein. In 98% of cases this codon is AUG, but alternative start codons in prokaryotes are common. For example, in bacteria the start codon is a modified amino acid N-formyl methionine, abbr. f-Met. In f-Met, the amino group is blocked by the formyl group to form an amide, so that this amino group cannot form pep�