Reverse translatase
Reverse translatase is a fictitious enzyme that could derive the formation instructions for a nucleic acid sequence from an amino acid sequence (as in a protein ) and thus catalyze the formation of the latter. This would mean that the step of creating an amino acid sequence from mRNA on the ribosomes would be logically reversed. However, this would overturn the central dogma of molecular biology , which, roughly speaking, describes the flow of information from nucleic acids to proteins as a "one-way street".
background
The retroviruses , which also include HIV, use the enzyme reverse transcriptase to copy their genetic information stored as RNA into DNA in order to then integrate this into the host genome. This fact allows us to consider why the path from the mRNA to the peptide cannot also be reversed. However, this is not observed in living organisms. Also of interest in this context is the so-called PNA , which does not occur naturally, but is suggested as a possible precursor molecule and thus as a template for the formation of RNA.
criticism
The following reasons speak against the existence or the biological meaning of any kind of "reverse translatase" or a corresponding reversal of translation:
The genetic code is degenerate. This means that several codons can code for an amino acid. Of the 64 different codons, 61 code for only 20 different proteinogenic amino acids; three codons encode stop signals. Thus it is impossible to obtain a translation of a given amino acid sequence into exactly one corresponding nucleic acid sequence. There are also proteinogenic amino acids such as selenocysteine that are not directly represented by a codon. Hydroxyproline, on the other hand, which is not considered a proteinogenic amino acid, makes up a large part of the amino acid sequence of collagens, but is not represented by a codon.
Others
The subject is the subject of the satire Das D2-Experiment .