Document Type
Article
Publication Date
12-11-2014
Abstract
Glutamyl-tRNA (Glu-tRNAGlu) is the common substrate for both protein translation and heme biosynthesis via the C5 pathway. Under normal conditions, an adequate supply of this aminoacyl-tRNA is available to both pathways. However, under certain circumstances, Glu-tRNAGlu can become scarce, resulting in competition between the two pathways for this aminoacyl-tRNA. In Acidithiobacillus ferrooxidans, glutamyl-tRNA synthetase 1 (GluRS1) is the main enzyme that synthesizes Glu-tRNAGlu. Previous studies have shown that GluRS1 is inactivated in vitro by hydrogen peroxide (H2O2). This raises the question as to whether H2O2 negatively affects in vivo GluRS1 activity in A. ferrooxidans and whether Glu-tRNAGlu distribution between the heme and protein biosynthesis processes may be affected by these conditions. To address this issue, we measured GluRS1 activity. We determined that GluRS1 is inactivated when cells are exposed to H2O2, with a concomitant reduction in intracellular heme level. The effects of H2O2 on the activity of purified glutamyl-tRNA reductase (GluTR), the key enzyme for heme biosynthesis, and on the elongation factor Tu (EF-Tu) were also measured. While exposing purified GluTR, the first enzyme of heme biosynthesis, to H2O2 resulted in its inactivation, the binding of glutamyl-tRNA to EF-Tu was not affected. Taken together, these data suggest that in A. ferrooxidans, the flow of glutamyl-tRNA is diverted from heme biosynthesis towards protein synthesis under oxidative stress conditions.
Recommended Citation
Farah, C., Levicán, G., Ibba, M. and Orellana, O. (2014) Effect of hydrogen peroxide on the biosynthesis of heme and proteins: potential implications for the partitioning of Glu-tRNAGlu between these pathways. Int. J. Mol. Sci. 15, 23011-23023. https://doi.org/10.3390/ijms151223011
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The authors
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Included in
Amino Acids, Peptides, and Proteins Commons, Biochemistry Commons, Cellular and Molecular Physiology Commons, Molecular Biology Commons, Nucleic Acids, Nucleotides, and Nucleosides Commons, Other Biochemistry, Biophysics, and Structural Biology Commons
Comments
This article was originally published in International Journal of Molecular Sciences, volume 15, in 2014. https://doi.org/10.3390/ijms151223011