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Summary Sentence: A Planetary Astrobiology Seminar by Aaron McKee
Full Summary: No summary paragraph submitted.
Aaron McKeeThe presence of amino acids (AA) on extraterrestrial bodies and in prebiotic simulation experiments suggests the plausibility of their existence on early Earth. In contrast to extant biological protein production, abiotic polypeptide formation presents several challenges, such as the thermodynamically unfavored condensation of non-activated AAs in aqueous solution.
Recent work has introduced α-hydroxy acids (HA), a class of molecules found alongside AA in prebiotic contexts, into peptide-forming systems. This has been shown as a robust route towards proto-polypeptides, producing long, mixed-acid oligomers, referred to as depsipeptides. In pursuit of realistic model prebiotic environments, mineral-molecule interactions must be considered and may facilitate new chemical pathways at interfacial regions.
Here we demonstrate that the inclusion of silica in HA/AA reactions effects the composition of oligomers, resulting in AA enrichment relative to a substrate-absent controls. Evidence of surface ester formation suggests that silica is directly involved in the oligomer growth process and departs from previous studies of mineral catalyzed peptide formation on metal oxides.
If depsipeptides are model proto-polypeptides, then surface functionalization of minerals with simple HAs might provide catalytic pathways useful for unraveling plausible routes to the production of complex molecules under early-Earth conditions or on extraterrestrial bodies.
About the Speaker
Aaron McKee is a Ph.D. candidate in the School of Chemistry and Biochemostry. He is conducting research at the NSF/NASA Center for Chemical Evolution.
