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The design, synthesis, and evolution of macrocyclic mRNA display libraries containing unnatural amino acids

Citation

Millward, Steven Wesley (2007) The design, synthesis, and evolution of macrocyclic mRNA display libraries containing unnatural amino acids. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-05142007-161158

Abstract

Combinatorial design is a powerful method for generating ligands that disrupt protein-protein interactions, particularly in the absence of structural information. mRNA display is powerful in vitro biological display technique that enables the synthesis and evolution of trillion-member peptide libraries. Previously, mRNA display libraries were limited to linear peptides composed entirely from natural (protegenic) amino acids. This work describes the redesign of mRNA display libraries to include chemical functionalities that hitherto have remained the province of traditional chemical libraries and natural products. The incorporation of unnatural (nonproteogenic) amino acids through nonsense suppression and selection for the unnatural chemical functionality demonstrated that suppression technologies were compatible with biological display. The incorporation of N-methylated amino acids by sequential sense suppression was shown to generate unnatural oligomers with improved proteolytic resistance. Post-translational macrocyclization was shown to be an effective and general strategy to constrain displayed peptides without the use of redox-labile disulfide bonds. Co-translational unnatural amino acid incorporation and post-translational macrocyclization were combined into a new technological platform and employed in the selection of a high-affinity cyclic ligand for G[alpha]i1. This new technology represents a significant step toward the evolution of natural product-like compounds from trillion-member combinatorial libraries.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:evolution; g-protein; macrocycle; mRNA display; N-methyl amino acids; peptide; selection; unnatural amino acid
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Biochemistry and Molecular Biophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Roberts, Richard W.
Thesis Committee:
  • Dervan, Peter B. (chair)
  • Dougherty, Dennis A.
  • Rothenberg, Ellen V.
  • Roberts, Richard W.
Defense Date:24 April 2007
Author Email:millward (AT) caltech.edu
Record Number:CaltechETD:etd-05142007-161158
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-05142007-161158
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5187
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:17 May 2007
Last Modified:26 Dec 2012 03:15

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