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Eufemio RJ, Schwidetzky R, Meister K. Measurement of Ice Nucleation Activity of Biological Samples. Methods Mol Biol 2024; 2730:101-107. [PMID: 37943453 DOI: 10.1007/978-1-0716-3503-2_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Experimentation with ice-nucleating biomolecules is needed to advance the fundamental understanding of biotic heterogeneous ice nucleation. Standard experimental procedures vary with sample type. Here we describe a generalized primary purification and analysis process to measure ice nucleation activity of biological samples using an advanced freezing droplet assay.
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Affiliation(s)
- Rosemary J Eufemio
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID, USA
| | | | - Konrad Meister
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID, USA.
- Max Planck Institute for Polymer Research, Mainz, Germany.
- Department of Chemistry and Biochemistry, Boise State University, Boise, ID, USA.
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2
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Schwidetzky R, de Almeida Ribeiro I, Bothen N, Backes AT, DeVries AL, Bonn M, Fröhlich-Nowoisky J, Molinero V, Meister K. Functional aggregation of cell-free proteins enables fungal ice nucleation. Proc Natl Acad Sci U S A 2023; 120:e2303243120. [PMID: 37943838 PMCID: PMC10655213 DOI: 10.1073/pnas.2303243120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 10/06/2023] [Indexed: 11/12/2023] Open
Abstract
Biological ice nucleation plays a key role in the survival of cold-adapted organisms. Several species of bacteria, fungi, and insects produce ice nucleators (INs) that enable ice formation at temperatures above -10 °C. Bacteria and fungi produce particularly potent INs that can promote water crystallization above -5 °C. Bacterial INs consist of extended protein units that aggregate to achieve superior functionality. Despite decades of research, the nature and identity of fungal INs remain elusive. Here, we combine ice nucleation measurements, physicochemical characterization, numerical modeling, and nucleation theory to shed light on the size and nature of the INs from the fungus Fusarium acuminatum. We find ice-binding and ice-shaping activity of Fusarium IN, suggesting a potential connection between ice growth promotion and inhibition. We demonstrate that fungal INs are composed of small 5.3 kDa protein subunits that assemble into ice-nucleating complexes that can contain more than 100 subunits. Fusarium INs retain high ice-nucleation activity even when only the ~12 kDa fraction of size-excluded proteins are initially present, suggesting robust pathways for their functional aggregation in cell-free aqueous environments. We conclude that the use of small proteins to build large assemblies is a common strategy among organisms to create potent biological INs.
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Affiliation(s)
- Ralph Schwidetzky
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz55128, Germany
| | | | - Nadine Bothen
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz55128, Germany
| | - Anna T. Backes
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz55128, Germany
| | - Arthur L. DeVries
- Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Mischa Bonn
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz55128, Germany
| | | | - Valeria Molinero
- Department of Chemistry, The University of Utah, Salt Lake City, UT84112
| | - Konrad Meister
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz55128, Germany
- Department of Chemistry and Biochemistry, Boise State University, Boise, ID83725
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3
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Abstract
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Bacterial ice nucleators
(INs) are among the most effective ice
nucleators known and are relevant for freezing processes in agriculture,
the atmosphere, and the biosphere. Their ability to facilitate ice
formation is due to specialized ice-nucleating proteins (INPs) anchored
to the outer bacterial cell membrane, enabling the crystallization
of water at temperatures up to −2 °C. In this Perspective,
we highlight the importance of functional aggregation of INPs for
the exceptionally high ice nucleation activity of bacterial ice nucleators.
We emphasize that the bacterial cell membrane, as well as environmental
conditions, is crucial for a precise functional INP aggregation. Interdisciplinary
approaches combining high-throughput droplet freezing assays with
advanced physicochemical tools and protein biochemistry are needed
to link changes in protein structure or protein–water interactions
with changes on the functional level.
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Affiliation(s)
- Max Lukas
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | | | | | - Mischa Bonn
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Konrad Meister
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany.,University of Alaska Southeast, Juneau, Alaska 99801, United States
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4
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Schwidetzky R, Sudera P, Backes AT, Pöschl U, Bonn M, Fröhlich-Nowoisky J, Meister K. Membranes Are Decisive for Maximum Freezing Efficiency of Bacterial Ice Nucleators. J Phys Chem Lett 2021; 12:10783-10787. [PMID: 34723523 PMCID: PMC8591660 DOI: 10.1021/acs.jpclett.1c03118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Ice-nucleating proteins (INPs) from Pseudomonas syringae are among the most active ice nucleators known, enabling ice formation at temperatures close to the melting point of water. The working mechanisms of INPs remain elusive, but their ice nucleation activity has been proposed to depend on the ability to form large INP aggregates. Here, we provide experimental evidence that INPs alone are not sufficient to achieve maximum freezing efficiency and that intact membranes are critical. Ice nucleation measurements of phospholipids and lipopolysaccharides show that these membrane components are not part of the active nucleation site but rather enable INP assembly. Substantially improved ice nucleation by INP assemblies is observed for deuterated water, indicating stabilization of assemblies by the stronger hydrogen bonds of D2O. Together, these results show that the degree of order/disorder and the assembly size are critically important in determining the extent to which bacterial INPs can facilitate ice nucleation.
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Affiliation(s)
- R. Schwidetzky
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - P. Sudera
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - A. T. Backes
- Max
Planck Institute for Chemistry, 55128 Mainz, Germany
| | - U. Pöschl
- Max
Planck Institute for Chemistry, 55128 Mainz, Germany
| | - M. Bonn
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | | | - K. Meister
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- University
of Alaska Southeast, Juneau, Alaska 99801, United States
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5
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Schwidetzky R, Lukas M, YazdanYar A, Kunert AT, Pöschl U, Domke KF, Fröhlich-Nowoisky J, Bonn M, Koop T, Nagata Y, Meister K. Specific Ion-Protein Interactions Influence Bacterial Ice Nucleation. Chemistry 2021; 27:7402-7407. [PMID: 33464680 PMCID: PMC8251952 DOI: 10.1002/chem.202004630] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Indexed: 11/12/2022]
Abstract
Ice nucleation‐active bacteria are the most efficient ice nucleators known, enabling the crystallization of water at temperatures close to 0 °C, thereby overcoming the kinetically hindered phase transition process at these conditions. Using highly specialized ice‐nucleating proteins (INPs), they can cause frost damage to plants and influence the formation of clouds and precipitation in the atmosphere. In nature, the bacteria are usually found in aqueous environments containing ions. The impact of ions on bacterial ice nucleation efficiency, however, has remained elusive. Here, we demonstrate that ions can profoundly influence the efficiency of bacterial ice nucleators in a manner that follows the Hofmeister series. Weakly hydrated ions inhibit bacterial ice nucleation whereas strongly hydrated ions apparently facilitate ice nucleation. Surface‐specific sum‐frequency generation spectroscopy and molecular dynamics simulations reveal that the different effects are due to specific interactions of the ions with the INPs on the surface of the bacteria. Our results demonstrate that heterogeneous ice nucleation facilitated by bacteria strongly depends upon the nature of the ions, and specific ion–protein interactions are essential for the complete description of heterogeneous ice nucleation by bacteria.
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Affiliation(s)
| | - Max Lukas
- Max Planck Institute for Polymer Research, 55128, Mainz, Germany
| | - Azade YazdanYar
- Max Planck Institute for Polymer Research, 55128, Mainz, Germany
| | - Anna T Kunert
- Max Planck Institute for Chemistry, 55128, Mainz, Germany
| | - Ulrich Pöschl
- Max Planck Institute for Chemistry, 55128, Mainz, Germany
| | - Katrin F Domke
- Max Planck Institute for Polymer Research, 55128, Mainz, Germany
| | | | - Mischa Bonn
- Max Planck Institute for Polymer Research, 55128, Mainz, Germany
| | - Thomas Koop
- Bielefeld University, 33615, Bielefeld, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, 55128, Mainz, Germany
| | - Konrad Meister
- Max Planck Institute for Polymer Research, 55128, Mainz, Germany.,University of Alaska Southeast, 99801, Juneau, AK, USA
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Abstract
Perfluorinated acids (PFAs) are widely used synthetic chemical compounds, highly resistant to environmental degradation. The widespread PFA contamination in remote regions such as the High Arctic implies currently not understood long-range atmospheric transport pathways. Here, we report that perfluorooctanoic acid (PFOA) initiates heterogeneous ice nucleation at temperatures as high as -16 °C. In contrast, the eight-carbon octanoic acid, perfluorooctanesulfonic acid, and deprotonated PFOA showed poor ice nucleating capabilities. The ice nucleation ability of PFOA correlates with the formation of a PFOA monolayer at the air-water interface, suggesting a mechanism in which the aligned hydroxyl groups of the carboxylic acid moieties provide a lattice matching to ice. The ice nucleation capabilities of fluorinated compounds like PFOA might be relevant for cloud glaciation in the atmosphere and the removal of these persistent pollutants by wet deposition.
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Affiliation(s)
| | - Yuling Sun
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | | | - Anna T. Kunert
- Max
Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Konrad Meister
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- University
of Alaska Southeast, Juneau, Alaska 99801, United States
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7
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Lukas M, Schwidetzky R, Kunert AT, Backus EHG, Pöschl U, Fröhlich-Nowoisky J, Bonn M, Meister K. Interfacial Water Ordering Is Insufficient to Explain Ice-Nucleating Protein Activity. J Phys Chem Lett 2021; 12:218-223. [PMID: 33326244 DOI: 10.1021/acs.jpclett.0c03163] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
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.
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Affiliation(s)
- Max Lukas
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | | | - Anna T Kunert
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
- Department of Physical Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Ulrich Pöschl
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | | | - Mischa Bonn
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Konrad Meister
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
- University of Alaska Southeast, Juneau, Alaska 99801, United States
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8
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Schwidetzky R, Kunert AT, Bonn M, Pöschl U, Ramløv H, DeVries AL, Fröhlich-Nowoisky J, Meister K. Inhibition of Bacterial Ice Nucleators Is Not an Intrinsic Property of Antifreeze Proteins. J Phys Chem B 2020; 124:4889-4895. [PMID: 32437152 DOI: 10.1021/acs.jpcb.0c03001] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cold-adapted organisms use antifreeze proteins (AFPs) or ice-nucleating proteins (INPs) for the survival in freezing habitats. AFPs have been reported to be able to inhibit the activity of INPs, a property that would be of great physiological relevance. The generality of this effect is not understood, and for the few known examples of INP inhibition by AFPs, the molecular mechanisms remain unclear. Here, we report a comprehensive evaluation of the effects of five different AFPs on the activity of bacterial ice nucleators using a high-throughput ice nucleation assay. We find that bacterial INPs are inhibited by certain AFPs, while others show no effect. Thus, the ability to inhibit the activity of INPs is not an intrinsic property of AFPs, and the interactions of INPs and different AFPs proceed through protein-specific rather than universal molecular mechanisms.
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Affiliation(s)
| | - Anna T Kunert
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Ulrich Pöschl
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | | | - Arthur L DeVries
- University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | | | - Konrad Meister
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany.,University of Alaska Southeast, Juneau, Alaska 99801, United States
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9
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Lukas M, Schwidetzky R, Kunert AT, Pöschl U, Fröhlich-Nowoisky J, Bonn M, Meister K. Electrostatic Interactions Control the Functionality of Bacterial Ice Nucleators. J Am Chem Soc 2020; 142:6842-6846. [PMID: 32223131 DOI: 10.1021/jacs.9b13069] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacterial ice-nucleating proteins (INPs) promote heterogeneous ice nucleation more efficiently than any other material. The details of their working mechanism remain elusive, but their high activity has been shown to involve the formation of functional INP aggregates. Here we reveal the importance of electrostatic interactions for the activity of INPs from the bacterium Pseudomonas syringae by combining a high-throughput ice nucleation assay with surface-specific sum-frequency generation spectroscopy. We determined the charge state of nonviable P. syringae as a function of pH by monitoring the degree of alignment of the interfacial water molecules and the corresponding ice nucleation activity. The net charge correlates with the ice nucleation activity of the INP aggregates, which is minimal at the isoelectric point. In contrast, the activity of INP monomers is less affected by pH changes. We conclude that electrostatic interactions play an essential role in the formation of the highly efficient functionally aligned INP aggregates, providing a mechanism for promoting aggregation under conditions of stress that prompt the bacteria to nucleate ice.
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Affiliation(s)
- M Lukas
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - R Schwidetzky
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - A T Kunert
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - U Pöschl
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | | | - M Bonn
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - K Meister
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany.,University of Alaska Southeast, Juneau, Alaska 99801, United States
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10
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Korschelt K, Schwidetzky R, Pfitzner F, Strugatchi J, Schilling C, von der Au M, Kirchhoff K, Panthöfer M, Lieberwirth I, Tahir MN, Hess C, Meermann B, Tremel W. CeO 2-x nanorods with intrinsic urease-like activity. Nanoscale 2018; 10:13074-13082. [PMID: 29961799 DOI: 10.1039/c8nr03556c] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The large-scale production and ecotoxicity of urea make its removal from wastewater a health and environmental challenge. Whereas the industrial removal of urea relies on hydrolysis at elevated temperatures and high pressure, nature solves the urea disposal problem with the enzyme urease under ambient conditions. We show that CeO2-x nanorods (NRs) act as the first and efficient green urease mimic that catalyzes the hydrolysis of urea under ambient conditions with an activity (kcat = 9.58 × 101 s-1) about one order of magnitude lower than that of the native jack bean urease. The surface properties of CeO2-x NRs were probed by varying the Ce4+/Ce3+ ratio through La doping. Although La substitution increased the number of surface defects, the reduced number of Ce4+ sites with higher Lewis acidity led to a slight decrease of their catalytic activity. CeO2-x NRs are stable against pH changes and even to the presence of transition metal ions like Cu2+, one of the strongest urease inhibitors. The low costs and environmental compatibility make CeO2-x NRs a green urease substitute that may be applied in polymer membranes for water processing or filters for the waste water reclamation. The biomimicry approach allows the application of CeO2-x NRs as functional enzyme mimics where the use of native or recombinant enzyme is hampered because of its costs or operational stability.
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Affiliation(s)
- K Korschelt
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, D-55128 Mainz, Germany.
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