Unnatural selection within a replicating peptide system
Abstract
In this work, a multi-component, replicating peptide system capable of both auto- and cross-catalysis, was successfully designed and demonstrated. Two peptides within the system were designed in such a way that they would only self-reproduce under extreme conditions, such as very high or low pH, or high concentrations of salts. The selective amplification of one or more products within the replicating peptide system was accomplished simply by changing the environmental conditions, such as pH or salt concentrations within the reaction vessel, thereby achieving processes analogous to natural selection within the system. While investigating the scope of this replicating system as a whole, we have demonstrated efficient cross-catalysis in seven unique peptide systems, and have added five new examples of self-replicating peptides. The process leading to the evolution of one particular product in our system was similar to the natural selection process, "survival of the fittest", proposed by the Darwinian theory of evolution. This is, to our knowledge, the first time that amplification of one or more molecules in a non-enzymatic, self-reproducing chemical system has been achieved through environmental changes. Therefore, our designed system is the first ever to demonstrate, in vitro, processes analogous to those of natural selection proposed by the Darwinian theory of evolution. Our system, therefore, could be termed a peptide-based, replicating system capable of "unnatural selection".
Degree
Ph.D.
Advisors
Chmielewski, Purdue University.
Subject Area
Organic chemistry|Biochemistry
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