Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Formation of complex biomolecules from simple biochemical building blocks

27.10.2015

Scientists from the Institute of Organic Chemistry at the University of Stuttgart have found that under certain conditions spontaneous reactions take place between ribonucleotides and amino acids, leading to molecules that contain both ribonucleic acid (RNA) and peptide chains. The findings suggest that a primitive form of protein synthesis could have preceded today's protein synthesis during prebiotic evolution. This makes it likely that life did not start with a pure 'RNA world' but with a molecular world in which RNA as well as very short protein chains were formed. The results were published in the international edition of Angewandte Chemie.

Life is based on a complex biochemical machinery. How this machinery arose from inanimate material is unclear. The most important biochemical machines are enzymes (proteins). The blueprints of the enzymes are encoded in DNA and are transcribed with the aid of both RNA and enzymes.


Cartoon representations of biochemical protein synthesis (left) and the spontaneous chemical processes found in the laboratory.

(Graphic by M. Jauker)


(Peptidyl-RNA, Peptides, Co-factors)

University of Stuttgart

Without enzymes, there is no transcription, and without genes and RNA there are no enzymes. Up to now the solution for this dilemma was presumed to be that a so-called 'RNA world' was first, in which RNA acted both as a genetic material and as biocatalyst. Yet, how the 'RNA-protein world' evolved from the RNA world was unclear.

Unexpected observation: formation of peptidyl RNAs

Researchers at the University of Stuttgart now report that spontaneous reactions take place between the basic building blocks of RNA, the ribonucleotides, and amino acids, if they come into contact with each other in a special aqueous buffer.

The buffer contains a condensation agent that induces a spontaneous condensation of the building blocks. Not just RNA chains form in the mixtures, but also mixed molecules, made up of an RNA portion and a peptide chain (proteins are long peptide chains). This mixed type of molecule is called peptidyl RNA. Certain parts of the biochemical machinery for protein synthesis may have evolved from peptidyl RNAs.

The observation came as a surprise. The research group of Professor Clemens Richert was searching for reaction conditions inducing enzyme-free copying of RNA sequences. When graduate student Mario Jauker used conditions mimicking ice-water mixtures that are found when seawater freezes and he added a potent condensation agent, he observed untemplated formation of new RNA chains

. Since the condensation agent, an organic derivative of the molecule cyanamide, is also used in peptide synthesis, chemical engineer Helmut Griesser then mixed amino acids to the RNA building blocks. Surprisingly, significant concentrations of peptidyl RNAs formed alongside RNA chains and some free peptides in the salty buffer solutions. More complex peptidyl RNAs are key intermediates of protein synthesis.

Cartoon representations of biochemical protein synthesis (left) and the spontaneous chemical processes found in the laboratory. Peptidyl RNAs arise from amino acids and nucleotides, which release peptides in the presence of acid. (Graphic by M. Jauker)

In today's protein synthesis (left-hand side of graphic), the peptide chain grows to a full-length protein by migrating from one charged transfer-RNA to the next, with one amino acid residue being added during each step according to the genetic code. Earlier attempts to induce the formation of peptidyl RNAs in the absence of enzymes were largely unsuccessful. It was believed that the so-called 'C-terminus' of the peptide chain and the phosphate group of the first ribonucleotide reacted with each other.

A detailed structural characterization at the Institute of Organic Chemistry, revealed that the 'N-terminus' of the peptide chain is linked to the phosphate instead. This explains why longer peptidyl RNAs were able to form, as this structural arrangement allows both the peptide chain and the RNA chain to grow simultaneously. When the scientists added acetic acid, fee peptides were released from the peptidyl RNAs.

Importantly, it is not just peptidyl RNAs that form in the aqueous condensation buffer employed. After adding other building blocks, the researchers were able to also detect compounds that play an important role in the metabolism of the cell. These include adenosine triphosphate (ATP), the 'energy currency' of the cell, as well as the cofactors NAD and FAD that are involved in the biosynthesis of many cellular components, as well as the energy metabolism of the cell.

A more conclusive picture emerges

It is now clear that under the same reaction conditions, simple genetic materials, peptides, and key molecules of a primitive metabolism can form from simple building blocks. Therefore no major evolutionary step appears to be necessary to get from an 'RNA world' to an 'RNA-protein world'. The latter may have evolved in a series of spontaneous steps via reactions that are related to those that lead to the formation of RNA chains. The observation that this happens under conditions that also lead to the spontaneous copying of genetic information makes these observations all the more fascinating. As Professor Richert put it: "It felt as if we were watching a play performed by molecules. A play that nature encoded by creating matter with properties more fascinating than the simple structure of the chemicals suggests." His team, that now also includes Svenja Kaspari, is currently working on reaction conditions that are closer to those that are found in the cell today.

Publications in the international edition of "Angewandte Chemie"

The Stuttgart researchers report the results of their studies in two publications that are being published in the journal Angewandte Chemie and that are accessible online without a subscription:
Mario Jauker, Helmut Griesser and Clemens Richert: “Copying RNA sequences without pre-activation", Angewandte Chemie International Edition (2015), DOI: 10.1002/anie.201506592 and "Spontaneous formation of RNA strands, peptidyl-RNA and co-factors", Angewandte Chemie International Edition (2015),: DOI: 10.1002/anie.201506593

Online-Versions:
https://doi.org/10.1002/anie.201506592 and https://doi.org/10.1002/anie.201506593

Contact:
Professor Clemens Richert, University of Stuttgart, Institute of Organic Chemistry, Tel. 0711/685-64311, Email: lehrstuhl-2 (at) oc.uni-stuttgart.de

Andrea Mayer-Grenu, University of Stuttgart, Abt. University Communication, Tel. 0711/685-82176, Email: andrea.mayer-grenu (at) hkom.uni-stuttgart.de

Andrea Mayer-Grenu | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-stuttgart.de/

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>