RNA World on Ice : A New Scenario for the Emergence of Life

Ivan Gladich

Hamad Bin Khalifa University

3 July 2018, 11:30 am

Abstract

The RNA world is a hypothetical time in the evolution of life on Earth when there was no elaborate protein synthesis and RNA emerged as both enzyme and information carrier. In the early Earth, the formation of RNA chains capable of self-copying could have enabled the transmission of genetic information from one generation to the other and, by mutations, the evolution toward more complex molecular machineries. RNA world has been suggested as the missing link between the prebiotic synthesis of biomolecules and the formation of first prokaryotic cells and DNA-based organisms. Nevertheless, this hypothesis is challenged by the fact that complex RNA structures would rapidly degraded under the conditions of the early Earth.

Recently, self-copying of single strand RNA (ssRNA) immobilized on a solid substrate has been observed experimentally at low temperatures. This suggests that prebiotic conditions associated with freezing, rather than ‘‘warm and wet’’ conditions, could have been of key importance in an early RNA world on ice. However, an RNA world on ice remains speculative because the interfacial mechanisms of formation and self-copying on ice are hardly accessible by experiments at atomistic resolution. Computer simulations based on atomistic molecular dynamics permit virtual experiments under plausible prebiotic conditions that are inaccessible or extremely costly in real laboratories, complementing the experimental work and driving new research and ideas.

After a general overview of the RNA world hypothesis within the Oparin-Miller-Urey framework for the origin of life, I shall present results from state-of-the-art molecular dynamics simulations on the solvation of ssRNA at the air/ice and air/supercooled liquid water interfaces. At the same temperature, the dynamics of ssRNA is slower on ice surface than the one on the supercooled liquid water, suggesting a strong interaction of the RNA backbone with the underlying crystalline structure. Moreover, on ice ssRNA is preferentially in an extended structural conformation, while on liquid water in a mis-folded arrangement. Finally, the water attack to the 2′-OH group of the ribose moieties is much less frequent on the surface of ice than on liquid water. These results suggest slower rates for RNA cleavage on ice and an easier self-copying mechanism of RNA in presence of free nucleotides in solution on the premelted surface of ice.

 

Bio-sketch

Dr. Ivan Gladich graduated in Physics at the University of Trieste in 2005. He completed his Ph.D. in Environmental and Industrial Fluid Mechanics at University of Trieste/International Center for Theoretical Physics (ICTP) in 2009. His thesis focused on problems in atmospheric physics and, in particular, on the tornado genesis in the troposphere.

From January 2009 to December 2010 he was Dreyfus postdoctoral associate in the department of chemistry at Purdue University, USA, while in 2013 he moved to Prague at the Institute of Organic Chemistry and Biochemistry/Czech Academy of Science. During these periods, Dr. Gladich worked on physicochemical processes involving atmospheric ice: the physics of freezing and melting and the solvation properties of small molecular ions and organic molecules in the ice-Quasi Liquid Layer.

In January 2013 he joined the International School for Advanced Studies (SISSA) in Trieste, Italy, working on the development of algorithms for the design of short peptides as receptor for small organic molecules, such as chemotherapy drugs, in different solvents.

Since June 2015 is permanent staff at the Qatar Environmental and Energy Research Institute, a department within the recently formed Hamad Bin Khalifa University, in Qatar. His work is primarily focused on the study of complex solute-solvent interactions at interfacial environments, in particular those of atmospheric relevance, providing physically justified inputs for reliable atmospheric weather and air-quality forecasts. Moreover, Dr. Gladich expertise ranges among different computational techniques and his publication record address problems of environmental, biological, and technological interest.

Last update: 20/11/2018