α-helical peptide Self-assembly Structure Design and Characterization 公开

Wang, Shengyuan (Spring 2021)

Permanent URL: https://etd.library.emory.edu/concern/etds/4m90dw74j?locale=zh
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Abstract

Functionalized nanomaterials are extensively researched in the past decades due to their high functionalization density, and unique physical and mechanical properties compared to their macro-scale material counterparts. Among them, protein and peptide-based nanomaterials are especially sought after, as they encode life-related functions that are often not accessible by current technologies. However, precise control and rational design of protein and peptide-based nanomaterials are difficult to achieve. This thesis presents the design and characterization of three α-helical peptide systems with the recently discovered, novel cross-α tertiary structure that self-assemble into nanofibrils, nanosheets from fibril lamination, and nanotubes from nanosheet wrapping; and the design and characterization of one α-helical coiled-coil peptide system with designed coiled-coil interfaces promoting 2D lateral association of coiled-coil bundles that self-assemble into nanosheets. The results will enhance our understandings of protein self-assembly principles and hopefully contribute to protein and peptide-based nanomaterial designs in the future.

Table of Contents

1..... Chapter 1: Introduction to 1D and 2D Self-assembled Peptide Nanomaterials 23

1.1       Introduction. 23

1.2       α-helix peptide self-assembly. 25

1.3       1D peptide self-assembly based on other structural motifs. 31

1.4       2D peptide self-assembly based on other structural motifs 37

1.5       Conclusion. 40

2..... Chapter 2: PSMα3 Selectively Self-assembles into cross-α Nanotubes 47

2.1       Introduction. 47

2.2       Results and discussion. 53

2.2.1        Self-assembly of PSMα3. 53

2.2.2        Characterization of PSMα3 nanotubes at pH 2. 58

2.2.3        Characterization of PSMα3 nanotubes at pH 8. 68

2.2.4        Screening of amphipathic peptides potentially posing cross-α structures 78

2.3       Conclusion. 81

2.4       Methods 83

3..... Chapter 3: PSMβ2 Self-assembles into cross-α Nanotubes 91

3.1       Introduction. 91

3.2       Results and discussion. 93

3.2.1        Self-assembly of PSMβ1. 93

3.2.2        Self-assembly of PSMβ2. 97

3.2.3        Structural Characterization of the PSMβ2 Nanotubes 101

3.2.4        Structural characterization of other PSMβ2 morphologies 115

3.3       Conclusion. 123

3.4       Methods 124

4..... Chapter 4: Designed Peptide Mimicking Cross-α Amyloid-like Fibrils 129

4.1       Introduction. 129

4.2       Results and discussion. 132

4.2.1        A designed cross cross-α fibril peptide ROX321. 132

4.2.2        Length variants of ROX321. 150

4.2.3        Stacking interface mutants of ROX321. 155

4.3       Conclusion. 161

4.4       Methods 163

5      Chapter 5: Designed 2D Assemblies via Engineering Inter-coiled-coil Bundle Interfaces 174

5.1       Introduction. 174

5.2       Results and discussion. 176

5.2.1        Designs of CC3V2, CC3V7 and CC3V8. 176

5.2.2        Self-assembly of CC3V2, CC3V7 and CC3V8. 181

5.3       Conclusion. 190

5.4       Methods 191

6..... Chapter 6: Conclusion. 200

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