Identifier

etd-0814102-133523

Abstract

"Ghadiri reported the first synthetic peptide nanotubue in 1993, which has triggered extensive studies on peptide-based nanotubes and their potential application in molecular wires, catalysts and novel drug delivery vehicles. Our concerns focus on chromophore-modified cyclic peptides, which open a new way to design and synthesize novel nanoscale electronic or photonic devices, and are expected to provide the highly efficient electron and energy transfer that such devices require. This research concerned the design and synthesis of chiral a-amino acids with specific chromophores, including N-ethyl-3-carbazolylalanine and 9-anthrylalanine, and an 8-mer linear peptide (H-Aib-Car-Aib-Phe-Aib-Bpa-Aib-Phe-OH) and its corresponding cyclic peptide cyclo(Aib-Car-Aib-Phe-Aib-Bpa-Aib-Phe) that incorporate the N-ethyl-3-carbazolylalanine. This thesis describes the relevant background, synthetic strategies, experiments and results in detail. The carbazole derivatives were found to be very labile to strong acid, which might have caused self-condensation. In order to avoid the formation of acid-derived side-products, the Wittig-Horner reaction was used successfully in preparation of N-protected-3-(N'-ethyl-3-carbazolyl)-DL-alanine methyl ester. Dual enzymatic hydrolyses were developed to produce the chiral amino acids with high enantiomeric excess. ChiroCLEC-BL was used to selectively hydrolyze the N-acetyl-L-amino acid methyl ester, while amanoacylase was adopted to remove the acetyl group from the resulting N-acetyl-L-amino acid. Two model peptides were synthesized, a 4-mer peptide (H-Car-D-Ala-Bpa-D-Ala-OH) via the Boc-strategy, and an 8-mer peptide (H-Ala-D-Ala-Npa-D-MeAla-Ala-D-Ala-Bpa-D-Ala-OH) by the Fmoc-strategy. Eventually, the target linear peptide was synthesized via the Fmoc-strategy and then cyclized in solution."

Publisher

Worcester Polytechnic Institute

Degree Name

MS

Department

Chemistry & Biochemistry

Project Type

Thesis

Date Accepted

2002-08-14

Accessibility

Unrestricted

Subjects

chromophore, N-ethyl-3-carbazolylalanine, 9-anthrylalanine, chiral amino acids, cyclic peptide, solid-phase peptide synthesis, enzymatic resolution, cyclization, Peptides, Nanostructures, Amino acids

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