https://dialnet.unirioja.es/descarga/articulo/4511387.pdf

The origins of order. Self-organization and selection in evolution

https://www.pnas.org/content/pnas/90/5/1635.full.pdf

Supramolecular chemistry.

A minimal cell can be thought of as comprising informational, compartment-forming and metabolic subsystems. To imagine the abiotic assembly of such an overall system, however, places great demands on hypothetical prebiotic chemistry. The perceived differences and incompatibilities between these subsystems have led to the widely held assumption that one or other subsystem must have preceded the others. Here we experimentally investigate the validity of this assumption by examining the assembly of various biomolecular building blocks from prebiotically plausible intermediates and one-carbon feedstock molecules. We show that precursors of ribonucleotides, amino acids and lipids can all be derived by the reductive homologation of hydrogen cyanide and some of its derivatives, and thus that all the cellular subsystems could have arisen simultaneously through common chemistry. The key reaction steps are driven by ultraviolet light, use hydrogen sulfide as the reductant and can be accelerated by Cu(I)–Cu(II) photoredox cycling. A minimal cell — one that has all the minimum requirements for life — is still a complex entity comprising informational, compartment-forming and metabolic subsystems. Here it is shown that, contrary to previous assumptions, a common prebiotically plausible chemistry can give rise to building blocks for all the subsystems.

/pdf/common-origins-of-rna-protein-and-lipid-precursors-in-a-3d1lstsl8z.pdf

Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism

Kepa Ruiz-Mirazo,†,∥ Carlos Briones,‡,∥ and Andreś de la Escosura* †Biophysics Unit (CSIC-UPV/EHU), Leioa, and Department of Logic and Philosophy of Science, University of the Basque Country, Avenida de Tolosa 70, 20080 Donostia−San Sebastiań, Spain ‡Department of Molecular Evolution, Centro de Astrobiología (CSIC−INTA, associated to the NASA Astrobiology Institute), Carretera de Ajalvir, Km 4, 28850 Torrejoń de Ardoz, Madrid, Spain Organic Chemistry Department, Universidad Autońoma de Madrid, Cantoblanco, 28049 Madrid, Spain

Prebiotic systems chemistry: new perspectives for the origins of life.

The continuity of abiotically formed bilayer membraneswith similar structures in contemporary cellular life,and the requirement for microenvironments in whichlarge and small molecules could be compartmentalized, support the idea that amphiphilic boundary structurescontributed to the emergence of life. As an extensionof this notion, we propose here a `Lipid World'scenario as an early evolutionary step in theemergence of cellular life on Earth. This conceptcombines the potential chemical activities of lipidsand other amphiphiles, with their capacity to undergospontaneous self-organization into supramolecularstructures such as micelles and bilayers. Inparticular, the documented chemical rate enhancementswithin lipid assemblies suggest that energy-dependentsynthetic reactions could lead to the growth andincreased abundance of certain amphiphilic assemblies.We further propose that selective processes might acton such assemblies, as suggested by our computersimulations of mutual catalysis among amphiphiles. Asdemonstrated also by other researchers, such mutualcatalysis within random molecular assemblies couldhave led to a primordial homeostatic system displayingrudimentary life-like properties. Taken together,these concepts provide a theoretical framework, andsuggest experimental tests for a Lipid World model forthe origin of life.

The lipid world.

Mutually catalytic sets of simple organic molecules have been suggested to be capable of self-replication and rudimentary chemical evolution. Previous models for the behavior of such sets have analyzed the global properties of short biopolymer ensembles by using graph theory and a mean field approach. In parallel, experimental studies with the autocatalytic formation of amphiphilic assemblies (e.g., lipid vesicles or micelles) demonstrated self-replication properties resembling those of living cells. Combining these approaches, we analyze here the kinetic behavior of small heterogeneous assemblies of spontaneously aggregating molecules, of the type that could form readily under prebiotic conditions. A statistical formalism for mutual rate enhancement is used to numerically simulate the detailed chemical kinetics within such assemblies. We demonstrate that a straightforward set of assumptions about kinetically enhanced recruitment of simple amphiphilic molecules, as well as about the spontaneous growth and splitting of assemblies, results in a complex population behavior. The assemblies manifest a significant degree of homeostasis, resembling the previously predicted quasi-stationary states of biopolymer ensembles (Dyson, F. J. (1982) J. Mol. Evol. 18, 344–350). Such emergent catalysis-driven, compositionally biased entities may be viewed as having rudimentary “compositional genomes.” Our analysis addresses the question of how mutually catalytic metabolic networks, devoid of sequence-based biopolymers, could exhibit transfer of chemical information and might undergo selection and evolution. This computed behavior may constitute a demonstration of natural selection in populations of molecules without genetic apparatus, suggesting a pathway from random molecular assemblies to a minimal protocell.

/pdf/compositional-genomes-prebiotic-information-transfer-in-4lbdb53bs0.pdf

Compositional genomes: Prebiotic information transfer in mutually catalytic noncovalent assemblies

The Graded Autocatalysis Replication Domain (GARD) model described here depicts an early primordial scenario, prior to the emergence of biopolymers, such as RNA or proteins. The model describes, with the help of statistical chemistry computer simulations, a collection of organic molecular species capable of rudimentary selection and evolution. The GARD model provides a rigorous kinetic analysis of simple sets of chemicals that manifest mutual catalysis. It is shown that catalytic closure can sustain self replication up to a critical dilution rate, related to the extent of mutual catalysis. The capacity for self replication in a mutually catalytic set is shown to be a graded property, quantitated by a critical parameter (lambda) ci. GARD could be a simple model for a primordial scenario, in which replication and catalysis are performed by the same set of molecules.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

/pdf/gardobes-primordial-cell-nano-precursors-with-organic-15k61r9b61.pdf

Dafna Ben-Eli

Papers

The lipid world.

Compositional genomes: Prebiotic information transfer in mutually catalytic noncovalent assemblies

GARDobes: primordial cell nano-precursors with organic catalysis, compositional genome, and capacity to evolve

Prebiotic Evolution of Amphiphilic Assemblies Far from Equilibrium