Date of Award

1-1-2016

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Chemistry

Content Description

1 online resource (xiv, 98 pages) : color illustrations.

Dissertation/Thesis Chair

John T Welch

Committee Members

Alexander Shekhtman, Jayanti Pande, Pan Li, Rabi Musah

Keywords

Chimeric polypeptide, Light-harvesting peptide, Proline-based triads, Synthetic amyloidogenic protein, β-Sheet, β-Sheet nucleation, Peptides, Protein folding

Subject Categories

Biochemistry | Molecular Biology

Abstract

The focus of the present research is the synthesis of polypeptides for the study of protein folding and misfolding and for the development of novel polypeptide-based optical antennas in nanotechnology. It is hypothesized that simple polypeptides can be used as models to mimic in vivo folding of globular proteins. Desired repetitive polypeptides were genetically encoded and expressed in E. coli using conventional methods and characterized using a variety of spectroscopic (including circular dichroism (CD), deep UV resonance Raman (DUVRR), UV-vis and fluorescence) and microscopic (atomic force microscopy (AFM) and transmission electron microscopy (TEM)) techniques. The polypeptides predominantly formed bilayer, fibrillar structures with a cross β-core. YEHK21-YE8, a chimeric polypeptide, folded within three days. The folding/fibrillation of the chimeric construct illuminates the controlling factors and hence suggests the importance of those factors in amyloidogenic diseases. YE8 and YE8 derivatives illustrated the role of proline in β-sheet formation. The EW polypeptide models elucidated the influence of tryptophan residues and the degree of polymerization on folding. The study of EW14C1 and EW21C1 demonstrated light-harvesting properties when labeled with a suitable dye.

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