Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces
The control of freezing saline water at the micrometer level has become very important in cryosurgery and cryopreservation of stem cells and foods. Adding antifreeze protein to saline water is a promising method for controlling the freezing because the protein produces a gap between the melting poin...
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MDPI AG
2018-07-01
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| Series: | Crystals |
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| Online Access: | http://www.mdpi.com/2073-4352/8/7/302 |
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| author | Tatsuya Yasui Tadashi Kaijima Ken Nishio Yoshimichi Hagiwara |
| author_facet | Tatsuya Yasui Tadashi Kaijima Ken Nishio Yoshimichi Hagiwara |
| author_sort | Tatsuya Yasui |
| collection | DOAJ |
| description | The control of freezing saline water at the micrometer level has become very important in cryosurgery and cryopreservation of stem cells and foods. Adding antifreeze protein to saline water is a promising method for controlling the freezing because the protein produces a gap between the melting point and the freezing point. Furthermore, a synergistic effect of the solutes occurs in which the freezing point depression of a mixed solution is more noticeable than the sum of two freezing point depressions of single-solute solutions. However, the mechanism of this effect has not yet been clarified. Thus, we have carried out a molecular dynamics simulation on aqueous solutions of winter flounder antifreeze protein and sodium chloride or calcium chloride with an ice layer. The results show that the cations inhibit the hydrogen bond among water molecules not only in the salt solutions but also in the mixed solutions. This inhibition depends on the local number of ions and the valence of cations. The space for water molecules to form the hydrogen bonds becomes small in the case of the mixed solution of the protein and calcium chloride. These findings are consistent with the synergistic effect. In addition, it is found that the diffusion of ions near positively-charged residues is attenuated. This attenuation causes an increase in the possibility of water molecules staying near or inside the hydration shells of the ions. Furthermore, the first hydration shells of the cations become weak in the vicinity of the arginine, lysine and glutamic-acid residues. These factors can be considered to be possible mechanisms of the synergistic effect. |
| first_indexed | 2024-04-11T18:25:31Z |
| format | Article |
| id | doaj.art-a197eb6d4c00446380b7283234991822 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-04-11T18:25:31Z |
| publishDate | 2018-07-01 |
| publisher | MDPI AG |
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| series | Crystals |
| spelling | doaj.art-a197eb6d4c00446380b72832349918222022-12-22T04:09:38ZengMDPI AGCrystals2073-43522018-07-018730210.3390/cryst8070302cryst8070302Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution SurfacesTatsuya Yasui0Tadashi Kaijima1Ken Nishio2Yoshimichi Hagiwara3Division of Mechanophysics, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JapanDivision of Mechanophysics, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JapanSchool of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JapanFaculty of Mechanical Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JapanThe control of freezing saline water at the micrometer level has become very important in cryosurgery and cryopreservation of stem cells and foods. Adding antifreeze protein to saline water is a promising method for controlling the freezing because the protein produces a gap between the melting point and the freezing point. Furthermore, a synergistic effect of the solutes occurs in which the freezing point depression of a mixed solution is more noticeable than the sum of two freezing point depressions of single-solute solutions. However, the mechanism of this effect has not yet been clarified. Thus, we have carried out a molecular dynamics simulation on aqueous solutions of winter flounder antifreeze protein and sodium chloride or calcium chloride with an ice layer. The results show that the cations inhibit the hydrogen bond among water molecules not only in the salt solutions but also in the mixed solutions. This inhibition depends on the local number of ions and the valence of cations. The space for water molecules to form the hydrogen bonds becomes small in the case of the mixed solution of the protein and calcium chloride. These findings are consistent with the synergistic effect. In addition, it is found that the diffusion of ions near positively-charged residues is attenuated. This attenuation causes an increase in the possibility of water molecules staying near or inside the hydration shells of the ions. Furthermore, the first hydration shells of the cations become weak in the vicinity of the arginine, lysine and glutamic-acid residues. These factors can be considered to be possible mechanisms of the synergistic effect.http://www.mdpi.com/2073-4352/8/7/302ice surfacewinter flounder antifreeze proteinsodium ionscalcium ionssynergistic effectsmolecular dynamics simulation |
| spellingShingle | Tatsuya Yasui Tadashi Kaijima Ken Nishio Yoshimichi Hagiwara Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces Crystals ice surface winter flounder antifreeze protein sodium ions calcium ions synergistic effects molecular dynamics simulation |
| title | Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces |
| title_full | Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces |
| title_fullStr | Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces |
| title_full_unstemmed | Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces |
| title_short | Molecular Dynamics Analysis of Synergistic Effects of Ions and Winter Flounder Antifreeze Protein Adjacent to Ice-Solution Surfaces |
| title_sort | molecular dynamics analysis of synergistic effects of ions and winter flounder antifreeze protein adjacent to ice solution surfaces |
| topic | ice surface winter flounder antifreeze protein sodium ions calcium ions synergistic effects molecular dynamics simulation |
| url | http://www.mdpi.com/2073-4352/8/7/302 |
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