Interfacial Water Ordering Is Insufficient to Explain Ice-Nucleating Protein Activity
| Autor: | Ralph Schwidetzky, Max Lukas, Ulrich Pöschl, Janine Fröhlich-Nowoisky, Ellen H. G. Backus, Mischa Bonn, Konrad Meister, Anna T. Kunert |
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| Přispěvatelé: | IoP (FNWI), Soft Matter (WZI, IoP, FNWI) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Aqueous solution
Chemistry 010401 analytical chemistry Supramolecular chemistry Pseudomonas syringae Water 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Solution structure 0104 chemical sciences law.invention Protein structure law Chemical physics Ice nucleus Molecule General Materials Science Protein activity Physical and Theoretical Chemistry Crystallization 0210 nano-technology Bacterial Outer Membrane Proteins |
| Zdroj: | The Journal of Physical Chemistry Letters Journal of Physical Chemistry Letters, 12(1), 218-223. American Chemical Society |
| ISSN: | 1948-7185 |
| Popis: | Ice-nucleating proteins (INPs) found in bacteria are the most effective ice nucleators known, enabling the crystallization of water at temperatures close to 0 °C. Although their function has been known for decades, the underlying mechanism is still under debate. Here, we show that INPs from Pseudomonas syringae in aqueous solution exhibit a defined solution structure and show no significant conformational changes upon cooling. In contrast, irreversible structural changes are observed upon heating to temperatures exceeding ∼55 °C, leading to a loss of the ice-nucleation activity. Sum-frequency generation (SFG) spectroscopy reveals that active and heat-inactivated INPs impose similar structural ordering of interfacial water molecules upon cooling. Our results demonstrate that increased water ordering is not sufficient to explain INPs' high ice-nucleation activity and confirm that intact three-dimensional protein structures are critical for bacterial ice nucleation, supporting a mechanism that depends on the INPs' supramolecular interactions. |
| Databáze: | OpenAIRE |
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