A Spectroscopic Study on Secondary Structure and Thermal Unfolding of the Plant Toxin Gelonin Confirms Some Typical Structural Characteristics and Unravels the Sequence of Thermal Unfolding Events
Abstract
:1. Introduction
2. Results and Discussion
2.1. Analysis of Gelonin Secondary Structure
2.2. Thermal Unfolding
2.3. The Sequence of the Thermal Unfolding Events
3. Conclusions
4. Materials and Methods
4.1. Materials
4.2. FTIR Spectra
4.3. Phase Diagram Method
4.4. Two-Dimensional Correlation Spectroscopy (2D-COS)
Author Contributions
Funding
Conflicts of Interest
References
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Band Assignment | Center (cm−1) | Area (%) |
---|---|---|
β-sheet (low frequency) | 1624 | 13 |
β-sheet | 1635 | 10 |
Unordered | 1646 | 22 |
α-helix | 1654 | 32 |
β-turns/310-helix | 1661 | 8 |
β-turns | 1672 | 12 |
β-turns/β-sheet (high frequency) | 1681 | 2 |
β-turns | 1692 | 1 |
Secondary Structure | This Work | X-ray Data | Circular Dichroism | Raman Spectroscopy |
---|---|---|---|---|
α-helix (including 310-helix) | 32–40 | 37 | > 29 | 32 |
β-sheet | 23–25 | 24 | 20 | |
Turns | 13–23 | 11 | 26 | |
Bend | 7 | |||
Unordered | 22 | 21 | 22 |
Synchronous Map | Asynchronous Map | |
---|---|---|
Auto-Peaks (cm−1) | Cross-Peaks at ν1/ν2 (cm−1) | Cross-Peaks at ν1/ν2 (cm−1) |
1683↑ | 1683↑/1618↑ + | 1683↑/1550↓ + a |
1654↓ | 1683↑/1654↓ − | 1683↑/1624↓ − a |
1618↑ | 1654↓/1550↓ + | 1683↑/1654↓ + a |
1654↓/1618↑ − | 1661↓/1550↓ − a | |
1654↓/1635↓ + | 1661↓/1618↑ − b | |
1635↓/1618↑ − | 1654↓/1550↓ − a | |
1618↑/1550↓ − | 1654↓/1618↑ − b | |
1654↓/1661↓ − a | ||
1654↓/1683↑ − b | ||
1624↓/1618↑ + b | ||
1618↑/1550↓ + a |
Unfolding Event | FTIR Band Assigment |
---|---|
First step (from 20 to 60 °C) | |
Tertiary structure relaxation | (1550↓) |
Second step (from 60 to 85 °C) | |
β-turns/310-helix denaturation | (1661↓) |
α-helix and β-sheet denaturation | (1654↓, 1624↓, 1635↓) |
Aggregation and β-turns denaturation | (1618↑, 1672↓) |
Aggregation | (1683↑) |
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Scirè, A.; Tanfani, F.; Ausili, A. A Spectroscopic Study on Secondary Structure and Thermal Unfolding of the Plant Toxin Gelonin Confirms Some Typical Structural Characteristics and Unravels the Sequence of Thermal Unfolding Events. Toxins 2019, 11, 483. https://doi.org/10.3390/toxins11090483
Scirè A, Tanfani F, Ausili A. A Spectroscopic Study on Secondary Structure and Thermal Unfolding of the Plant Toxin Gelonin Confirms Some Typical Structural Characteristics and Unravels the Sequence of Thermal Unfolding Events. Toxins. 2019; 11(9):483. https://doi.org/10.3390/toxins11090483
Chicago/Turabian StyleScirè, Andrea, Fabio Tanfani, and Alessio Ausili. 2019. "A Spectroscopic Study on Secondary Structure and Thermal Unfolding of the Plant Toxin Gelonin Confirms Some Typical Structural Characteristics and Unravels the Sequence of Thermal Unfolding Events" Toxins 11, no. 9: 483. https://doi.org/10.3390/toxins11090483
APA StyleScirè, A., Tanfani, F., & Ausili, A. (2019). A Spectroscopic Study on Secondary Structure and Thermal Unfolding of the Plant Toxin Gelonin Confirms Some Typical Structural Characteristics and Unravels the Sequence of Thermal Unfolding Events. Toxins, 11(9), 483. https://doi.org/10.3390/toxins11090483