Prebiotic Synthesis of Protobiopolymers Under Alkaline Ocean Conditions

• Published in: Origins of life and evolution of biospheres 2011-08, Vol.41 (4), p.331-345
• Main Authors: Ruiz-Bermejo, Marta, Rivas, Luis A., Palacín, Arantxa, Menor-Salván, César, Osuna-Esteban, Susana
• Format: Article
• Language: English
• Subjects: Aerosols; Aerosols - chemistry; Astronomy; Astrophysics and Astroparticles; Atmosphere; Biochemistry; Biomedical and Life Sciences; Biopolymers; Biosphere; Carbon aerosols; Carboxylic acids; Carboxylic Acids - chemical synthesis; Chemical Fractionation - methods; Chemical oceanography; Chemical synthesis; Earth Sciences; Electricity; Electrophoresis; Electrophoresis, Gel, Two-Dimensional - methods; Electrophoresis, Polyacrylamide Gel - methods; Energy sources; Evolution, Chemical; Gas Chromatography-Mass Spectrometry - methods; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Inorganic carbon; Life Sciences; Methane - chemistry; Molecular biology; Molecular weight; Observations and Techniques; Oceans; Oceans and Seas; Polymers; Polymers - chemical synthesis; Polymers - chemistry; Prebiotic Chemistry; Quaternary Ammonium Compounds - chemistry; Salinity; Spectrophotometry, Infrared - methods; Tricarboxylic acid cycle
• ISSN: 0169-6149; 1573-0875
• DOI: 10.1007/s11084-010-9232-z

Clasically, prebiotic chemistry has focused on the production and identification of simple organic molecules, many of them forming part of “intractable polymers” named tholins . In a previous work, we demonstrated that in experiments using an external energy source and inorganic carbon the aqueous aerosols improved the formation of hydrophilic tholins . Herein, we elucidate the role of pH (from 4 to 12) in prebiotic experiments using saline aqueous aerosols, spark discharges and an atmosphere containing CH 4 . At all values of pH, the saline aqueous aerosols increased the production of a significant variety of carboxylic acids that could have been present in a primitive Krebs cycle. Moreover, the study for the first time of hydrophilic tholins by 2-D electrophoresis revealed that these are formed by a set of unexpected heavy polymeric species. The initial alkaline conditions significantly increased both the apparent molecular weight of polymeric species up to 80 kDa and their diversity. We propose the term of protobiopolymers to denote those polymeric species fractionated by 2-D electrophoresis since these are formed by biomolecules present in living systems and show diversity in length as well as in functional groups. Thus, aerosols formed in simulated alkaline ocean conditions could provide an optimal medium for the formation of the primeval materials that could be precursors to the emergence of life.