engleski

Effect of mistranslation and oxidative stress on growth and viability of bacteria Escherichia coli

Translation is a cellular process in which nucleotide sequence is translated to protein sequence whereby enzymes aminoacyl-tRNA synthetases play an important role in catalysis of aminoacyl-tRNA synthesis. During translation process, incorporation of the wrong amino acid in the polypeptide chain can occur. Mistranslation is usually associated with deleterious effects it has on a cell, but there are few examples of beneficial effects of mistranslation in stress conditions. Escherichia coli strain expressing mutant isoleucyl-tRNA synthetase with inactivated editing domain produces mistranslated proteins if proteinogenic amino acid valine or nonproteinogenic norvaline, which are structurally similar to isoleucine, are added to the media. Mistranslation was induced by adding different concentrations of valine or norvaline and oxidative stress was induced by adding H2O2. Bacteria observed under microscope displayed morphological change in oxidative and, more significantly, in mistranslation stress conditions. The cells were considerably longer compared to control with size increasing in a concentration-dependent manner by adding valine or norvaline. To observe the effect of stress on cell proliferation and viability, growth curves were measured, and survival assays were performed. The results indicate that there is mistranslation-induced preadaptation to oxidative stress, albeit only in a narrow range of valine and norvaline concentrations. Further work will be focused on identification of cellular mechanisms that allow better survival under oxidative stress due to mistranslation.

mistranslation ; oxidative stress ; isoleucyl-tRNA synthetase

nije evidentirano