As proteins are synthesized during messenger RNA translation, fresh amino acids are delivered to the ribosome of the cell by nucleic acid molecules known as transfer RNAs (tRNAs). Each amino acid has a cognate tRNA, and the two are joined by specialized enzymes known as aminoacyl-tRNA synthetases (aaRS).
Scientists have also identified a number of bacterial aaRS paralogs, counterparts that resemble these enzymes but lack key functional domains. The role of these proteins is mostly a mystery, but a team led by Shigeyuki Yokoyama at the RIKEN Systems and Structural Biology Center in Yokohama has now revealed an unexpected function for the Escherichia coli aaRS paralog GenX1.
“I thought that elucidation of the structure and function of aaRS paralogs would lead to an understanding of not only mechanisms of genetic code translation but also the evolution of living organisms,” explains Yokoyama. In fact, GenX is closely related to the aaRS that transfers the amino acid lysine; although it can no longer bind lysine’s tRNA, it still associates strongly with lysine, and on the whole these two proteins are highly similar in structure.
This similarity suggested to the team that GenX transfers lysine to a different molecular target, subsequently identified as elongation factor P (EF-P): a translation-associated protein whose structure closely resembles the distinctive L-shape of tRNA molecules. “This is the first discovery of such striking similarities in structure and function between a nucleic acid and a protein, although they are completely different molecules,” says Yokoyama. He proposes that these two molecules may have come to resemble each other by a process of ‘convergent evolution’, which favored the ability to productively interact with such closely related enzymes (Fig. 1).
Although it is extremely common for one protein to modulate the activity of another by attaching one of a selection of chemical groups, this represents the first known example of a protein being modified by the enzymatic addition of an entire amino acid. Nevertheless, the researchers demonstrated that this activity plays a vital role in protein production by E. coli cells, and is therefore essential to their survival.
Yokoyama now hopes to more closely explore the details of this process, but he also sees the potential for short-term applications as well. “GenX exists only in bacterial species, such as E. coli and Salmonella, and not in eukaryotic organisms, such as humans,” he says. “Therefore, GenX is a promising target for developing new antimicrobial agents for pathogenic bacteria … without adverse side effects.”
The corresponding author for this highlight is based at the RIKEN Systems and Structural Biology Center
1. Yanagisawa, T., Sumida, T., Ishii, R., Takemoto, C. & Yokoyama, S. A paralog of lysyl-tRNA synthetase aminoacylates a conserved lysine residue in translation elongation factor P. Nature Structural & Molecular Biology 17, 1136–1143 (2010).
A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich
New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
20.02.2017 | Materials Sciences
20.02.2017 | Health and Medicine
20.02.2017 | Health and Medicine