Monday, 23 July, 2018

The Birth of Biological Information

CAS Research Group

 

The new catalyst system functions as a multifunctional tool for splitting water. Image: C. Hohmann, NIM.

Biophysicist Dieter Braun studies how life and the chemistry that made it possible originated on the early Earth. He is now leading a research focus at the Center for Advanced Studies, and other interdisciplinary prestige projects at LMU such as the Collaborative Research Center 235 “Emergence of Life” with the DFG.

You study the origin of life. Where does it come from? What is your own basic idea of the origin of life?
Braun: A great deal must have happened on the Earth before living organisms – life as it is generally understood – could have emerged, even the simplest ones. Biological evolution, based on competition between organisms, was preceded by a phase of chemical evolution, of molecular evolution. The question at the center of our research is: How could molecular evolution have given rise to biological information? We approach the problem from the physicist’s perspective: How could prebiotic systems, systems that are not in equilibrium have made that possible? In the beginning, there were simple chemical building blocks, molecules that had to be linked together to form polymers, RNA or DNA – the macromolecules in whose subunit sequences biological information is encoded. Such a polymerization process cannot occur spontaneously. It must be driven by the environment. Because we have been able to recapitulate some of the necessary steps in laboratory experiments, we now have a good idea of the kind of environment in which this process took place. Hydrothermal vents or volcanic settings, where geothermically heated water emerges from vents in volcanic rock onto the seafloor, provide the basic setting. Here one finds tiny, water-filled rock pores in which temperature gradients are steep. And – from a physical point of view – we think that this is all one needs to drive such a system.

In your view, how did non-living matter make the transition to the living state?
Defining what exactly distinguishes living from non-living systems, what life really is one of the goals of this research. One possible answer is that one can use the term ‘life’ only when we have a – biological – cell. Others take the view that molecules that are capable of undergoing open-ended Darwinian evolution are already alive.

Source: Press release LMU