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Title: Nucleic acids at the mineral interface : an origins of life study
Author: Swadling, J. B.
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2013
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This thesis details work which employs classical simulation techniques to investigate the interactions of nucleic acid molecules with various charged clay mineral environments. There is a focus on the structure and stability of nucleic acids at mineral interfaces in order to understand how geological settings aided in fostering the first biomolecules at the time of the origins of life on Earth. A comparison of three nucleic acids, DNA, RNA and PNA, shows a difference in preferential stability in bulk water over the corresponding nucleic acid in a mineral environment. The comparative study showed that the prevailing geochemistry preferentially favoured DNA over potentially competing genetic candidates, such as RNA and PNA. This gives us a unique insight into how there may have been a transition from a proto-DNA world (such as the RNA world) to the current DNA/protein world. The structure and arrangement of single-stranded RNA on both cationic and anionic charged surfaces showed marked differences. Both cationic and anionic surfaces successfully adsorb on charged RNA oligonucleotides but show significant differences in the adsorbed structure. Cationic surfaces are successful in mediating the collapse of the RNA sequence from an elongated linear polymer into one that is capable of exhibiting catalytic function. The anionic surface elongates the RNA polymer and exposes the information carrying base sequence to the aqueous region allowing fidelity in templating information and replicating sequences. Studies of single-stranded RNA were extended to model a large biologically relevant RNA ribozyme using replica exchange sampling methods. The results elucidated the structure and arrangement of the catalytic centre of the ribozyme. The results in this thesis show that mineral mediated origins of life differ considerably from an aqueous one that is more commonly associated with the origins of life.
Supervisor: Coveney, P. V. ; Greenwell, H. C. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available