To path indicator Subpages of “Studies“ To navigation by target groups To navigation by topic To quick access To footer with other services
To content
lecture hall with a lot of students © Jürgen Huhn​/​TU Dortmund
TWO ARTICLES PUBLISHED IN NATURE COMMUNICATIONS

Chemists Study the Role of the Environment in the Emergence of Life

-
in
  • Top News
  • Research
photo of Prof. Hannes Mutschler © Ralf Maserski
Professor Hannes Mutschler has been Professor of Biomimetic Chemistry at the Department of Chemistry and Chemical Biology of TU Dortmund University since 2020.
The organisms we know today are composed of cells that use complex, well-timed mechanisms to duplicate their genetic material and divide it equally, producing two cells and allowing the organism to grow. Protein-based enzymes play a particularly important role in this process. However, these were not yet present in primitive precursors of life. Using experimental model systems, researchers study how putative primordial life forms were able to reproduce themselves in the absence of proteins and how this could ultimately have led to the emergence of life as we know it. Hannes Mutschler, Professor of Biomimetic Chemistry at the Department of Chemistry and Chemical Biology, and colleagues have now been able to demonstrate how external environmental oscillations can determine the timing of reproductive processes and could thus have assumed the task of modern enzymes. The researchers have published their findings in two articles in the prestigious journal Nature Communications.

The precise regulation of the reproduction of today’s cells is the product of millions of years of evolution. In contrast, it remains enigmatic how far more primitive precursors of life could have reproduced in the first place without the rich repertoire of protein-based enzymes. “One hypothesis suggests that in these primordial forms it was ribonucleic acids, in short RNA, that assumed the role of both DNA and enzymes, while external environmental influences determined the timing of reproduction,” explains Professor Mutschler. “We have studied the influence of the external environment on RNA replication in the laboratory. In the process, we have achieved two experimental breakthroughs that support exactly this assumption.”

Cyclic temperature fluctuations

Together with colleagues from the Max Planck Institute of Biochemistry in Martinsried, Professor Mutschler’s research group was able to show that simple freeze-thaw cycles facilitate the propagation of self-replicating RNA molecules in populations of simple protocells. The temperature fluctuations cause the membranes of the cell vesicles to become permeable for a short time, which enables the RNA replicators to infect them like primitive “viruses” and then to multiply there. The process was shown to be stable and could be perpetuated over several generations in the laboratory.

Click here for the article 

Microscopic water cycles

In the second paper, Professor Mutschler’s group together with biophysicists from LMU Munich present an experimental approach to solving the problem of the protein-free replication of genetic sequences. While the repeated reading and copying of sequence information from genomes is an everyday task for modern organisms thanks to modern protein enzymes, this process is much more problematic in purely RNA-based systems. One of the main problems in this context is that copied RNA sequences “stick” to each other like glue, which makes them unreadable if no proteins are present. Now, however, the researchers may have succeeded in finding a potentially suitable environment on early Earth that could have prevented the formation of these “dead-end duplexes”. These environments resemble small rock pores partly filled with liquid and a CO2-rich atmosphere, which are additionally exposed to a heat source on one side. Under these conditions, microscopic water cycles develop in the pores, in which the RNA molecules are exposed to cyclic changes in pH and salt concentrations. In combination with other effects, primitive RNA sequences can be repeatedly copied and even smaller “RNA genes” can be successfully transcribed in these environments, which were presumably very common on early Earth.

Click here for the article 

In future projects, the research groups want to combine the findings from both projects and produce experimental models for protocells with actively replicating genomes. This would represent an important contribution to understanding plausible scenarios of how life emerged.

Contact for queries:

Back

To top of page