Noam Adir

URSs, as mentioned, inhibit protein translation and may be fatal to the cell and the entire organism. The right part of the diagram shows their "damage mechanism", and the left part of the diagram shows a normal and normal process in the absence of URSs. Above: The genetic information, which encodes the sequence of amino acids, reaches the ribosome with the help of a molecule called mRNA. Amino acids (colored circles) join into a sequence and the new protein is pushed out of the exit channel of the ribosome. On the left side we see a normal sequence that creates normal proteins, while on the right side the row of amino acids contains the strong URS CMYW (in E. coli bacteria), which inhibits the protein on its way out and thus prevents the translation of additional proteins. In the middle: on the left side the proteins are organized in normal clusters, while on the right side - under the influence of the URS - less normal proteins are translated and damaged proteins are formed that were not translated to the end. Below: E. coli cells grow on plates in the presence (+) or absence (-) of IPTG - a substance that causes protein translation. On the left, i.e. on the normal side where the translated protein (+) does not contain URS, the number of bacterial colonies is the same as the number of bacterial colonies that grew without a translation command (-). On the right, on the disrupted side where the translated protein contains a URS (+), the number of colonies is much smaller than the number of colonies grown without the translation command (-).

Molecular evolution eliminates lethal sequences

General structure of the skin layer together with melanocyte cells and a melanoma type cancer tumor. Photo: shutterstock.

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