First Advisor

Niles Lehman

Term of Graduation

Summer 2008

Date of Publication

9-3-2008

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.) in Chemistry

Department

Chemistry

Language

English

Subjects

RNA, Catalytic RNA, Autocatalysis, Life -- Origin

DOI

10.15760/etd.7847

Physical Description

1 online resource (2, vii, 101 pages)

Abstract

This research demonstrates chemical reactions of RNA molecules that allow them to increase in length, from non-catalytic oligomers to complex RNA enzymes. The purpose of this research was to explain the origin of large RNA polymers required for life to begin in the proposed "RNA World". To do this, the Azoarcus group I ribozyme was engineered to catalyze phosphodiester exchange reactions that result in the recombination of short oligomer substrates marked by 5'CAU3' recognition tags.

To demonstrate the ability to produce catalytic RNA sequences through recombination, substrate oligomers were synthesized that could produce ribozymes if large portions of each sequence were recombined into a single molecule. The results demonstrated: (i) complex structures, such as the class I ligase ribozyme, can be constructed through the recombination of shorter substrates by the Azoarcus ribozyme, (ii) that the Azoarcus ribozyme itself can be constructed through recombination of shorter substrates, (iii) the "substrates" alone can catalyze the production of the Azoarcus ribozyme by forming non-covalent ribozyme complexes, (iv) the construction of the Azoarcus ribozyme from shorter substrates leads to autocatalysis, and (v) low level mutants of the Azoarcus ribozyme are the most likely to be assembled into covalent ribozymes when starting from a pool of mutated "substrates". These results demonstrate that large RNA molecules can arise from shorter oligomers through recombination. Moreover, complex phenotypes can spontaneously emerge from groups of RNA molecules giving rise to selection at the chemical level.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/

This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Comments

If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to pdxscholar@pdx.edu and include clear identification of the work, preferably with URL.

Persistent Identifier

https://archives.pdx.edu/ds/psu/37742

Download

Included in

Chemistry Commons

Share

COinS