The search for the chemical origins of life represents a long-standing and continuously debated enigma. Despite its exceptional complexity, in the last decades the field has experienced a revival, also owing to the exponential growth of the computing power allowing for efficiently simulating the behavior of matter-including its quantum nature-under disparate conditions found, e.g., on the primordial Earth and on Earth-like planetary systems (i.e., exoplanets). In this minireview, we focus on some advanced computational methods capable of efficiently solving the Schro¨dinger equation at different levels of approximation (i.e., density functional theory)-such as ab initio molecular dynamics-and which are capable to realistically simulate the behavior of matter under the action of energy sources available in prebiotic contexts. In addition, recently developed metadynamics methods coupled with first-principles simulations are here reviewed and exploited to answer to old enigmas and to propose novel scenarios in the exponentially growing research field embedding the study of the chemical origins of life.

• Klíčová slova
• ab initio molecular dynamics, astrobiology, density functional theory, metadynamics, origins of life, prebiotic chemistry,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Molecular Darwinian evolution is an intrinsic property of reacting pools of molecules resulting in the adaptation of the system to changing conditions. It has no a priori aim. From the point of view of the origin of life, Darwinian selection behavior, when spontaneously emerging in the ensembles of molecules composing prebiotic pools, initiates subsequent evolution of increasingly complex and innovative chemical information. On the conservation side, it is a posteriori observed that numerous biological processes are based on prebiotically promptly made compounds, as proposed by the concept of Chemomimesis. Molecular Darwinian evolution and Chemomimesis are principles acting in balanced cooperation in the frame of Systems Chemistry. The one-pot synthesis of nucleosides in radical chemistry conditions is possibly a telling example of the operation of these principles. Other indications of similar cases of molecular evolution can be found among biogenic processes.

• Klíčová slova
• Chemomimesis, Molecular Darwinism, origin of life, systems chemistry,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Recent results in prebiotic chemistry implicate hydrogen cyanide (HCN) as the source of carbon and nitrogen for the synthesis of nucleotide, amino acid and lipid building blocks. HCN can be produced during impact events by reprocessing of carbonaceous and nitrogenous materials from both the impactor and the atmosphere; it can also be produced from these materials by electrical discharge. Here we investigate the effect of high energy events on a range of starting mixtures representative of various atmosphere-impactor volatile combinations. Using continuously scanning time-resolved spectrometry, we have detected ·CN radical and excited CO as the initially most abundant products. Cyano radicals and excited carbon monoxide molecules in particular are reactive, energy-rich species, but are resilient owing to favourable Franck-Condon factors. The subsequent reactions of these first formed excited species lead to the production of ground-state prebiotic building blocks, principally HCN.

• MeSH
• atmosféra * MeSH
• dusík chemie   MeSH
• kyanovodík chemie   MeSH
• oxid uhelnatý chemie   MeSH
• prebiotika * MeSH
• uhlík chemie   MeSH
• Země (planeta) * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dusík MeSH
• kyanovodík MeSH
• oxid uhelnatý MeSH
• prebiotika * MeSH
• uhlík MeSH

The Miller-Urey experiments pioneered modern research on the molecular origins of life, but their actual relevance in this field was later questioned because the gas mixture used in their research is considered too reducing with respect to the most accepted hypotheses for the conditions on primordial Earth. In particular, the production of only amino acids has been taken as evidence of the limited relevance of the results. Here, we report an experimental work, combined with state-of-the-art computational methods, in which both electric discharge and laser-driven plasma impact simulations were carried out in a reducing atmosphere containing NH3 + CO. We show that RNA nucleobases are synthesized in these experiments, strongly supporting the possibility of the emergence of biologically relevant molecules in a reducing atmosphere. The reconstructed synthetic pathways indicate that small radicals and formamide play a crucial role, in agreement with a number of recent experimental and theoretical results.

• Klíčová slova
• asteroid impact, life origins, reducing atmosphere,
• MeSH
• amoniak chemie   MeSH
• atmosféra MeSH
• chemické modely MeSH
• evoluce chemická MeSH
• formamidy chemie   MeSH
• oxid uhelnatý chemie   MeSH
• oxidace-redukce MeSH
• původ života MeSH
• RNA chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amoniak MeSH
• formamide MeSH Prohlížeč
• formamidy MeSH
• oxid uhelnatý MeSH
• RNA MeSH