| Summary: | Peptide-based materials constitute a class of molecules that play an important role in many biological processes and are utilized by many organisms to interact with their environment. One of the most well-known examples is spider silk, a material produced by web-spinning spiders composed of repeating stretches of amino acids that has a very high tensile strength. Many peptide-based materials are composed of repeating stretches of certain amino acids that confer function and (macroscopic) structure to these materials. In the first three research chapters a peptide material based on naturally occurring antifreeze molecules from arctic fish is described. In nature this material is composed of repeating stretches of a glycosylated tripeptide. Our mimic is synthesized by a copper-catalyzed polymerization reaction from a modified glycotripeptide with polymerization handles. This polymerization reaction introduces a non-natural element in the peptide backbone that was known to mimic the natural amide bond in previously published examples to a certain extent. A one-pot reduction and polymerization yielded a mixture of oligomers that could be separated by size. Upon analysis of the antifreeze activity of the resulting antifreeze mimics by an ice recrystallization experiment, the polymeric material was shown to have a strongly reduced antifreeze activity compared to the natural compound and a synthetic derivative synthesized previously. Structural analysis by circular dichroism showed a similar structure to the previously described and potent synthetic antifreeze glycopeptide, indicating that a small structural change can abolish the potent antifreeze properties of such molecules. The chemistry for introducing a urea moiety that can be incorporated into the antifreeze glycopeptides to enhance the interaction with the ice-lattice is described, using a 4-chlorophenyl glycoside synthon that can react with amines under mild conditions to form a ureido glycoside linkage. As a case study, this chemistry was used to synthesize a ...
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