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Meléndez-López A, Cruz-Castañeda J, Negrón-Mendoza A, Ramos-Bernal S, Heredia A, Castro-Sanpedro L, Aguilar-Flores D. Gamma irradiation of adenine and guanine adsorbed into hectorite and attapulgite. Heliyon 2023; 9:e16071. [PMID: 37215897 PMCID: PMC10196509 DOI: 10.1016/j.heliyon.2023.e16071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
This study focuses on the radiolysis (up to 36 kGy) of guanine and adenine (nitrogenous bases) adsorbed in hectorite and attapulgite to highlight the potential role of clays as protective agents against ionizing radiation in prebiotic processes. In this framework, the study investigated the nitrogenous bases' behavior in two types of systems: a) aqueous suspension of adenine-clay systems and b) guanine-clay systems in the solid state. This research utilized spectroscopic and chromatographic techniques for its analytical purposes. Regardless of the reaction medium conditions, the results reveal that nitrogenous bases are stable under ionizing irradiation when adsorbed on both clays.
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Affiliation(s)
- A. Meléndez-López
- Instituto de Ciencias Nucleares, Circuito Exterior s/n, Ciudad Universitaria, Col. Universidad Nacional Autónoma de México, Deleg. Coyoacán, Apartado Postal 70-543, C.P. 04510, CDMX, Mexico
| | - J. Cruz-Castañeda
- Instituto de Ciencias Nucleares, Circuito Exterior s/n, Ciudad Universitaria, Col. Universidad Nacional Autónoma de México, Deleg. Coyoacán, Apartado Postal 70-543, C.P. 04510, CDMX, Mexico
| | - A. Negrón-Mendoza
- Instituto de Ciencias Nucleares, Circuito Exterior s/n, Ciudad Universitaria, Col. Universidad Nacional Autónoma de México, Deleg. Coyoacán, Apartado Postal 70-543, C.P. 04510, CDMX, Mexico
| | - S. Ramos-Bernal
- Instituto de Ciencias Nucleares, Circuito Exterior s/n, Ciudad Universitaria, Col. Universidad Nacional Autónoma de México, Deleg. Coyoacán, Apartado Postal 70-543, C.P. 04510, CDMX, Mexico
| | - A. Heredia
- Instituto de Ciencias Nucleares, Circuito Exterior s/n, Ciudad Universitaria, Col. Universidad Nacional Autónoma de México, Deleg. Coyoacán, Apartado Postal 70-543, C.P. 04510, CDMX, Mexico
| | - L.G. Castro-Sanpedro
- Facultad de Estudios Superiores Zaragoza Campus 2. Batalla 5 de Mayo s/n, Ejército de Oriente Zona Peñón, Iztapalapa, 09230, CDMX, Mexico
| | - D. Aguilar-Flores
- Facultad de Estudios Superiores Zaragoza Campus 2. Batalla 5 de Mayo s/n, Ejército de Oriente Zona Peñón, Iztapalapa, 09230, CDMX, Mexico
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Namani T, Ruf RJ, Arsano I, Hu R, Wesdemiotis C, Sahai N. Novel Chimeric Amino Acid-Fatty Alcohol Ester Amphiphiles Self-Assemble into Stable Primitive Membranes in Diverse Geological Settings. ASTROBIOLOGY 2023; 23:327-343. [PMID: 36724479 DOI: 10.1089/ast.2022.0056] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Primitive cells are believed to have been self-assembled vesicular structures with minimal metabolic components, that were capable of self-maintenance and self-propagation in early Earth geological settings. The coevolution and self-assembly of biomolecules, such as amphiphiles, peptides, and nucleic acids, or their precursors, were essential for protocell emergence. Here, we present a novel class of amphiphiles-amino acid-fatty alcohol esters-that self-assemble into stable primitive membrane compartments under a wide range of geochemical conditions. Glycine n-octyl ester (GOE) and isoleucine n-octyl ester (IOE), the condensation ester products of glycine or isoleucine with octanol (OcOH), are expected to form at a mild temperature by wet-dry cycles. The GOE forms micelles in acidic aqueous solutions (pH 2-7) and vesicles at intermediate pH (pH 7.3-8.2). When mixed with cosurfactants (octanoic acid [OcA]; OcOH, or decanol) in different mole fractions [XCosurfactant = 0.1-0.5], the vesicle stability range expands significantly to span the extremely acidic to mildly alkaline (pH 2-8) and extremely alkaline (pH 10-11) regions. Only a small mole fraction of cosurfactant [XCosurfactant = 0.1] is needed to make stable vesicular structures. Notably, these GOE-based vesicles are also stable in the presence of high concentrations of divalent cations, even at low pHs and in simulated Hadean seawater composition (without sulfate). To better understand the self-assembly behavior of GOE-based systems, we devised complementary molecular dynamics computer simulations for a series of mixed GOE/OcA systems under simulated acidic pHs. The resulting calculated critical packing parameter values and self-assembly behavior were consistent with our experimental findings. The IOE is expected to show similar self-assembly behavior. Thus, amino acid-fatty alcohol esters, a novel chimeric amphiphile class composed of an amino acid head group and a fatty alcohol tail, may have aided in building protocell membranes, which were stable in a wide variety of geochemical circumstances and were conducive to supporting replication and self-maintenance. The present work contributes to our body of work supporting our hypothesis for synergism and coevolution of (proto)biomolecules on early Earth.
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Affiliation(s)
- Trishool Namani
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio, USA
| | - Reghan J Ruf
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio, USA
- Integrated Biosciences Program, University of Akron, Akron, Ohio, USA
| | - Iskinder Arsano
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio, USA
| | - Ruibo Hu
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio, USA
| | - Chrys Wesdemiotis
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio, USA
- Department of Chemistry, University of Akron, Akron, Ohio, USA
| | - Nita Sahai
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio, USA
- Integrated Biosciences Program, University of Akron, Akron, Ohio, USA
- Department of Geosciences, and University of Akron, Akron, Ohio, USA
- Department of Biology, University of Akron, Akron, Ohio, USA
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