Gel-Sol transition of peptides derived from α-synuclein

다국어 초록 (Multilingual Abstract)

α-synuclein is a 140 residue protein, expressed in neurons. Through the specific self-assembly process, α-synuclein make insoluble protein aggregates such as Lewy bodies, the common characteristic of Parkinson’s disease. The self-assembly of α-synuclein becomes popular because of its pathological reason and also non disease functional role. Using TANGO program to predict amyloidogenic propensity, we found a specific sequence, based on α-synuclein sequence (35-40) , EGVLYV. Although this sequence is not located in NAC region (61-95), core region of the fibrillation process of α-synuclein, when this sequence becomes tandem repeat, EGVLYV-EGVLYV, the modified peptide shows Gel-Sol transition. The self-assembly of peptide from α-synuclein is studied in DMSO. The self-assembled structure (gel state) is transformed into sol state by applying proper force. When force is removed, the Sol state structure becomes Gel state. The assembled of peptide shows honey comb structure, confirmed by scanning electron microscopy. The characterization of Gel-Sol transition is proved by Advanced Rheometric Expansion System (ARES). The structure differences between Sol state and Gel state are proved by circular dichroism, and FT-IR. Comparing with other peptide gel, the peptide structure has a unique property such as Gel-Sol transition. Mechanical force sensitive self-assembled peptide is made by using peptide derived from α-synuclein. This novel peptide will be used to make mechanical sensitive materials.

목차 (Table of Contents)

• Contents
• 1. Introduction
• 1.1 α-synuclein and Parkinson’s Disease....................1
• 1.2 Self assembly application.....................................2
• 1.3 TANGO program..................................................2
• 2. Materials and Methods
• 2.1 Materials...........................................................3
• 2.2 Synthesis of peptide...........................................3
• 2.3 Field-Emission Scanning Electron Microscope (FE-SEM).......................................................................4
• 2.4 Circular Dichroism (CD) spectroscopy..................4
• 2.5 Advanced Rheometric Expansion System (ARES)..5
• 2.6 Fourier Trnasform Infrared Spectroscopy (FTIR).....5
• 3. Results and Discussion
• 3.1 Gel-Sol transition of the modified peptide sequence, based on α-synuclein (35-40).....................................6
• 3.2 Conditions of Gel-Sol transition
• 3.2.1 Sequence or tandem repeat effect of Gel-Sol transition...................................................................9
• 3.2.2 Peptide concentration effect of Gel-Sol transition...................................................................9
• 3.2.3 Solvent exchange effect of Gel-Sol transition.....11
• 3.2.4 Temperature effect of Gel-Sol transition............11
• 3.3 Characterization of Gel-Sol transition.
• 3.3.1 Internal structure of gel state peptide................16
• 3.3.2 Structural difference between sol state and gel state........................................................................16
• 3.3.3 Reversibility of Gel-Sol transition.....................17
• 3.3.4 Strain sweep test of Gel-Sol transition..............18
• 4. Conclusion............................................................27
• 5. References............................................................29
• 국문 초록..................................................................32