Mobility of a Mononucleotide within a Lipid Matrix: A Neutron Scattering Study.

Loreto Misuraca,Bruno Demé,David Deamer,Giuseppe Zaccai,Valerie Laux-Lesourd,Judith Peters,Jacques Ollivier,Michael Haertlein,Laura Da Silva,Tilo Seydel,Marie Maurel,Francesca Natali

doi:10.3390/life7010002

Abstract

An essential question in studies on the origins of life is how nucleic acids were first synthesized and then incorporated into compartments about 4 billion years ago. A recent discovery is that guided polymerization within organizing matrices could promote a non-enzymatic condensation reaction allowing the formation of RNA-like polymers, followed by encapsulation in lipid membranes. Here, we used neutron scattering and deuterium labelling to investigate 5′-adenosine monophosphate (AMP) molecules captured in a multilamellar phospholipid matrix. The aim of the research was to determine and compare how mononucleotides are captured and differently organized within matrices and multilamellar phospholipid structures and to explore the role of water in organizing the system to determine at which level the system becomes sufficiently anhydrous to lock the AMP molecules into an organized structure and initiate ester bond synthesis. Elastic incoherent neutron scattering experiments were thus employed to investigate the changes of the dynamic properties of AMP induced by embedding the molecules within the lipid matrix. The influence of AMP addition to the lipid membrane organization was determined through diffraction measurement, which also helped us to define the best working Q range for dynamical data analysis with respect to specific hydration. The use of different complementary instruments allowed coverage of a wide time-scale domain, from ns to ps, of atomic mean square fluctuations, providing evidence of a well-defined dependence of the AMP dynamics on the hydration level.

Highlights

Several scenarios related to the first steps of the origins of life have for the most part been investigated independently from one another
50 -adenosine monophosphate (AMP) molecules captured in a multilamellar phospholipid matrix composed of a mixture of phospholipids extracted from Pichia pastoris cells [13]; this could help to understand the formation of RNA-like polymers
We used neutron scattering to investigate AMP molecules captured in a multilamellar phospholipid matrix composed of a mixture of phospholipids extracted from Pichia pastoris cells [13] to study the formation of RNA-like polymers

Summary

Introduction

Several scenarios related to the first steps of the origins of life have for the most part been investigated independently from one another. RNA has the dual capacity of being a carrier of genetic information and a catalyst of chemical transformations, and is a convincing candidate as an ancestral biopolymer [2,3,4,5] It is not clear how a non-biological process could have synthesized random polymers of RNA-like molecules as a first step toward living systems. Non-enzymatic syntheses of RNA-like polymers from ordinary mononucleotides have been recently studied in simulated prebiotic conditions undergoing cycles of hydration–dehydration at an elevated temperature [6,7,8]

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