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dc.rights.licenseRestricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.
dc.contributorMcGown, Linda Baine
dc.contributorLinhardt, Robert J.
dc.contributorBae, Chulsung
dc.contributorWatson, E. Bruce
dc.contributorRogers, Karyn
dc.contributor.authorCoari, Kristin M.
dc.date.accessioned2021-11-03T08:32:33Z
dc.date.available2021-11-03T08:32:33Z
dc.date.created2016-02-26T09:19:40Z
dc.date.issued2015-12
dc.identifier.urihttps://hdl.handle.net/20.500.13015/1616
dc.descriptionDecember 2015
dc.descriptionSchool of Science
dc.description.abstractThe origins of life are of particular interest to the scientific community and the field of astrobiology. Multitudes of hypotheses have been offered to tackle the question of how life first developed on Earth. Some have focused primarily on the origin of the chemical components leading to the first molecules of life, such as the creation of amino acids, sugars, and nucleobases and their more complex analogues such as nucleotides. Others have focused on the polymerization of these components to form peptides, polysaccharides, and polynucleotides. Still others have focused on the organization of multiple components to form proto-cells as precursors to life. The RNA World Hypothesis focuses on RNA polymers as the first functioning biomolecule of life; still, proponents of the hypothesis have yet to identify a route to accommodate the sequence constraints that we see in modern biology.
dc.description.abstractFinally, in an effort to more closely mimic prebiotic Earth conditions, an alternative activation method was used. Instead of using nucleotides that were pre-activated, nucleotides were activated on-the-fly during polymerization reactions. Multiple nucleotide species were activated in a single pot synthesis to investigate the possible effects of the nucleobase in the activation process as well as the final polymer products. More combinations of polymer products were detected for these reactions, and as was the case for pre-activated nucleotides, there was selectivity toward polymerization of some nucleotides over others.
dc.description.abstractIt was found that some nucleotides polymerized to greater extents, and that the degree of heteropolymerization products was heavily dependent upon the type of ImpXs used. The presence of purine nucleotides led to much greater diversity in the polymerization products compared to pyrimidine nucleotides. In addition to the four nucleotides found in modern RNA, we also included inosine monophosphate, which is the nucleotide of the nucleobase hypoxanthine, in reactions of mixtures of activated nucleotides. It behaved similarly to other purines in terms of polymerization and its effect on the diversity of polymerization products.
dc.description.abstractTo address this question, RNA polymerization reactions were performed utilizing an activated nucleotide (ImpX), a catalytic mineral surface, and unactivated nucleotides. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths of polymer products as well as the nucleotide composition of the final polymer chains. These results show that unactivated nucleotides could be incorporated by abiotic RNA polymerization, and that this incorporation of an unactivated nucleotide included in these reactions was dependent upon the nucleobase of the ImpX. The results further show that there is selectivity toward incorporation of a terminating, unactivated nucleotide and in the composition of polymer products from reactions of mixtures of ImpX.
dc.description.abstractModern RNA uses four canonical nucleobases – adenine, guanine, cytosine, and uracil – transcribed from DNA and translated into proteins consisting of amino acid polymers. These nucleobases, however, were not likely to be the only ones present on a prebiotic Earth, even if they were available at all. This is best evidenced by the presence of other purine nucleobases in meteorites, as meteorite bombardment was a frequent event on Earth during or just before the origins of life. Additionally, some of the nucleobases, like guanine, are capable of self-assembly into large, aggregate structures known as G-tetrads and G-quadruplexes. These self-assembled aggregates could have functioned as a barrier to guanine's incorporation into RNA polymers, yet it is present as one of the canonical nucleobases. This paradox causes us to consider the mechanisms which may have influenced early nucleotide selection, particularly whether all available nucleotides would be equally likely to be incorporated into a growing RNA strand or if there would be selectivity toward some over others.
dc.language.isoENG
dc.publisherRensselaer Polytechnic Institute, Troy, NY
dc.relation.ispartofRensselaer Theses and Dissertations Online Collection
dc.subjectChemistry
dc.titleReactions and analysis investigating the nucleobase impacts on abiotic RNA polymerization
dc.typeElectronic thesis
dc.typeThesis
dc.digitool.pid177057
dc.digitool.pid177058
dc.digitool.pid177059
dc.rights.holderThis electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
dc.description.degreePhD
dc.relation.departmentDept. of Chemistry and Chemical Biology


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