title: Simple mechanisms of early life - simulation model on the origin of semi-cells.
abstract: The development of first cellular structures played an important role in the early evolution of life. Early evolution of life probably took place on a molecular level in a reactive environment. The iron-sulfur theory postulates the formation of cell-like structures on catalytic surfaces. Experiments show that H2S together with FeS and other metallic centers drive auto-catalytic surface reactions, in which organic molecules such as pyruvic and amino acids occur. It is questionable which mechanisms are needed to form cell-like structures under these conditions. To address this question, we implemented a model system featuring the fundamentals of molecular dynamics: heat, attraction, repulsion and formation of covalent bonds. Our basic model exhibits a series of essential processes: self-organization of lipid micelles and bilayers, formation of fluid filled cavities, flux of molecules along membranes, transport of energized groups towards sinks and whole colonies of cell-like structures on a larger scale. The results demonstrate that only a few features are sufficient for discovering hitherto non described phenomena of self-assembly and dynamics of cell-like structures as candidates for early evolving proto-cells. Significance statement The quest for a possible origin of life continues to be one of the most fascinating problems in biology. In one theoretical scenario, early life originated from a solution of reactive chemicals in the ancient deep sea, similar to conditions as to be found in thermal vents. Experiments have shown that a variety of organic molecules, the building blocks of life, form under these conditions. Based on such experiments, the iron-sulfur theory postulates the growth of cell-like structures at certain catalytic surfaces. For an explanation and proof of such a process we have developed a computer model simulating molecular assembly of lipid bilayers and formation of semi-cell cavities. The results demonstrate the possibility of cell-like self-organization under appropriate physico-chemical conditions.
authors.affiliation: Institute of Zoology, Poppelsdorfer Schloss, 53115 Bonn, Germany. Electronic address: adrian@uni-bonn.de.
authors.forename: Adrian
authors.initials: A
authors.lastname: Klein
authors.affiliation: Former Group of Theoretical Biology, University of Bonn, 53115 Bonn, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bock
authors.affiliation: Former Group of Theoretical Biology, University of Bonn, 53115 Bonn, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Alt
mesh_terms: D000465:Algorithms; D005075:Biological Evolution; D002384:Catalysis; D002451:Cell Compartmentation; D002477:Cells / Q000737:chemistry* / Q000166:cytology; D003198:Computer Simulation; D019418:Evolution, Chemical; D005296:Ferrous Compounds / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry; D000069497:Origin of Life; D010084:Oxidation-Reduction; D010316:Particle Size; D013447:Sulfites / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D005296:Ferrous Compounds; D008051:Lipid Bilayers; D009930:Organic Chemicals; D013447:Sulfites; D006859:Hydrogen; C042345:hydrogen sulfite; C022597:ferrous sulfide
keywords: Evolution; Iron-sulfur theory; Lipid bilayer; Origin of life; Particle dynamics; Proto-cell