1
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Han Q, Veríssimo NVP, Bryant SJ, Martin AV, Huang Y, Pereira JFB, Santos-Ebinuma VC, Zhai J, Bryant G, Drummond CJ, Greaves TL. Scattering approaches to unravel protein solution behaviors in ionic liquids and deep eutectic solvents: From basic principles to recent developments. Adv Colloid Interface Sci 2024; 331:103242. [PMID: 38964196 DOI: 10.1016/j.cis.2024.103242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 06/17/2024] [Accepted: 06/19/2024] [Indexed: 07/06/2024]
Abstract
Proteins in ionic liquids (ILs) and deep eutectic solvents (DESs) have gained significant attention due to their potential applications in various fields, including biocatalysis, bioseparation, biomolecular delivery, and structural biology. Scattering approaches including dynamic light scattering (DLS) and small-angle X-ray and neutron scattering (SAXS and SANS) have been used to understand the solution behavior of proteins at the nanoscale and microscale. This review provides a thorough exploration of the application of these scattering techniques to elucidate protein properties in ILs and DESs. Specifically, the review begins with the theoretical foundations of the relevant scattering approaches and describes the essential solvent properties of ILs and DESs linked to scattering such as refractive index, scattering length density, ion-pairs, liquid nanostructure, solvent aggregation, and specific ion effects. Next, a detailed introduction is provided on protein properties such as type, concentration, size, flexibility and structure as observed through scattering methodologies. This is followed by a review of the literature on the use of scattering for proteins in ILs and DESs. It is highlighted that enhanced data analysis and modeling tools are necessary for assessing protein flexibility and structure, and for understanding protein hydration, aggregation and specific ion effects. It is also noted that complementary approaches are recommended for comprehensively understanding the behavior of proteins in solution due to the complex interplay of factors, including ion-binding, dynamic hydration, intermolecular interactions, and specific ion effects. Finally, the challenges and potential research directions for this field are proposed, including experimental design, data analysis approaches, and supporting methods to obtain fundamental understandings of complex protein behavior and protein systems in solution. We envisage that this review will support further studies of protein interface science, and in particular studies on solvent and ion effects on proteins.
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Affiliation(s)
- Qi Han
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
| | - Nathalia V P Veríssimo
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto 14040-020, Brazil
| | - Saffron J Bryant
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Andrew V Martin
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Yuhong Huang
- Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Jorge F B Pereira
- Univ Coimbra, CERES, Department of Chemical Engineering, Pólo II - Pinhal de Marrocos, Coimbra 3030-790, Portugal
| | - Valéria C Santos-Ebinuma
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto 14040-020, Brazil
| | - Jiali Zhai
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Gary Bryant
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
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2
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Bharmoria P, Tietze AA, Mondal D, Kang TS, Kumar A, Freire MG. Do Ionic Liquids Exhibit the Required Characteristics to Dissolve, Extract, Stabilize, and Purify Proteins? Past-Present-Future Assessment. Chem Rev 2024; 124:3037-3084. [PMID: 38437627 PMCID: PMC10979405 DOI: 10.1021/acs.chemrev.3c00551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 02/08/2024] [Accepted: 02/19/2024] [Indexed: 03/06/2024]
Abstract
Proteins are highly labile molecules, thus requiring the presence of appropriate solvents and excipients in their liquid milieu to keep their stability and biological activity. In this field, ionic liquids (ILs) have gained momentum in the past years, with a relevant number of works reporting their successful use to dissolve, stabilize, extract, and purify proteins. Different approaches in protein-IL systems have been reported, namely, proteins dissolved in (i) neat ILs, (ii) ILs as co-solvents, (iii) ILs as adjuvants, (iv) ILs as surfactants, (v) ILs as phase-forming components of aqueous biphasic systems, and (vi) IL-polymer-protein/peptide conjugates. Herein, we critically analyze the works published to date and provide a comprehensive understanding of the IL-protein interactions affecting the stability, conformational alteration, unfolding, misfolding, and refolding of proteins while providing directions for future studies in view of imminent applications. Overall, it has been found that the stability or purification of proteins by ILs is bispecific and depends on the structure of both the IL and the protein. The most promising IL-protein systems are identified, which is valuable when foreseeing market applications of ILs, e.g., in "protein packaging" and "detergent applications". Future directions and other possibilities of IL-protein systems in light-harvesting and biotechnology/biomedical applications are discussed.
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Affiliation(s)
- Pankaj Bharmoria
- CICECO
- Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
- Department
of Smart Molecular, Inorganic and Hybrid Materials, Institute of Materials Science of Barcelona (ICMAB-CSIC), 08193 Bellaterra, Barcelona, Spain
- Department
of Chemistry and Molecular Biology, Wallenberg Centre for Molecular
and Translational Medicine, University of
Gothenburg, SE-412 96 Göteborg, Sweden
| | - Alesia A. Tietze
- Department
of Chemistry and Molecular Biology, Wallenberg Centre for Molecular
and Translational Medicine, University of
Gothenburg, SE-412 96 Göteborg, Sweden
| | - Dibyendu Mondal
- CICECO
- Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
- Institute
of Plant Genetics (IPG), Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland
- Centre
for Nano and Material Sciences, JAIN (Deemed-to-be
University), Jain Global
Campus, Bangalore 562112, India
| | - Tejwant Singh Kang
- Department
of Chemistry, UGC Center for Advance Studies-II,
Guru Nanak Dev University (GNDU), Amritsar 143005, Punjab, India
| | - Arvind Kumar
- Salt
and Marine Chemicals Division, CSIR-Central
Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar 364002, Gujarat, India
| | - Mara G Freire
- CICECO
- Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
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3
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Awad MN, Brown SJ, Abraham AN, Sezer D, Han Q, Wang X, Le TC, Elbourne A, Bryant G, Greaves TL, Bryant SJ. Biophysical Characterization and Cryopreservation of Mammalian Cells Using Ionic Liquids. J Phys Chem B 2024; 128:2504-2515. [PMID: 38416751 DOI: 10.1021/acs.jpcb.3c06797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024]
Abstract
Ionic liquids (ILs) are a diverse class of solvents which can be selected for task-specific properties, making them attractive alternatives to traditional solvents. To tailor ILs for specific biological applications, it is necessary to understand the structure-property relationships of ILs and their interactions with cells. Here, a selection of carboxylate anion-based ILs were investigated as cryoprotectants, which are compounds added to cells before freezing to mitigate lethal freezing damage. The cytotoxicity, cell permeability, thermal behavior, and cryoprotective efficacy of the ILs were assessed with two model mammalian cell lines. We found that the biophysical interactions, including permeability of the ILs, were influenced by considering the IL pair together, rather than as single species acting independently. All of the ILs tested had high cytotoxicity, but ethylammonium acetate demonstrated good cryoprotective efficacy for both cell types tested. These results demonstrate that despite toxicity, ILs may be suitable for certain biological applications. It also demonstrates that more research is required to understand the contribution of ion pairs to structure-property relationships and that knowing the behavior of a single ionic species will not necessarily predict its behavior as part of an IL.
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Affiliation(s)
- Miyah N Awad
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Stuart J Brown
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Amanda N Abraham
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
- ARC Centre of Excellence for Nanoscale BioPhotonics, RMIT University, Melbourne, Victoria 3001, Australia
| | - Dilek Sezer
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Qi Han
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Xiaoying Wang
- School of Engineering, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
- Digital Services, Deakin University, Melbourne, Victoria 3008, Australia
| | - Tu C Le
- School of Engineering, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Aaron Elbourne
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Gary Bryant
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Tamar L Greaves
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
| | - Saffron J Bryant
- School of Science, College of STEM, RMIT University, Melbourne, Victoria 3000, Australia
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4
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Brown SJ, Ryan TM, Drummond CJ, Greaves TL, Han Q. Lysozyme aggregation and unfolding in ionic liquid solvents: Insights from small angle X-ray scattering and high throughput screening. J Colloid Interface Sci 2024; 655:133-144. [PMID: 37931553 DOI: 10.1016/j.jcis.2023.10.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 10/09/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023]
Abstract
Understanding protein behaviour is crucial for developing functional solvent systems. Ionic liquids (ILs) are designer salts with versatile ion combinations, where some suppress unfavourable protein behaviour. This work utilizes small angle X-ray scattering (SAXS) to investigate the size and shape changes of model protein hen egg white lysozyme (HEWL) in 137 IL and salt solutions. Guinier, Kratky, and pair distance distribution analysis were used to evaluate the protein size, shape, and aggregation changes in these solvents. At low IL and salt concentration (1 mol%), HEWL remained monodispersed and globular. Most ILs increased HEWL size compared to buffer, while the nitrate and mesylate anions induced the most significant size increases. IL cation branching, hydroxyl groups, and longer alkyl chains counteracted this size increase. Common salts exhibited specific ion effects, while the IL effect varied with concentration due to complex ion-pairing. Protein aggregation and unfolding occurred at 10 mol% IL, altering the protein shape, especially for ILs with multiple alkyl chains on the cation, or with a mesylate/nitrate anion. This study highlights the usefulness of adopting a high-throughput SAXS strategy for understanding IL effects on protein behaviour and provides insights on controlling protein aggregation and unfolding with ILs.
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Affiliation(s)
- Stuart J Brown
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Timothy M Ryan
- SAXS/WAXS Beamline, Australian Synchrotron, 800 Blackburn Rd, Clayton, VIC 3168, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
| | - Qi Han
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
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5
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Han Q, Su Y, Smith KM, Binns J, Drummond CJ, Darmanin C, Greaves TL. Probing ion-binding at a protein interface: Modulation of protein properties by ionic liquids. J Colloid Interface Sci 2023; 650:1393-1405. [PMID: 37480654 DOI: 10.1016/j.jcis.2023.07.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 07/24/2023]
Abstract
Ions are important to modulate protein properties, including solubility and stability, through specific ion effects. Ionic liquids (ILs) are designer salts with versatile ion combinations with great potential to control protein properties. Although protein-ion binding of common metals is well-known, the IL effect on proteins is not well understood. Here, we employ the model protein lysozyme in dilute and concentrated IL solutions to determine the specific ion binding effect on protein phase behaviour, activity, size and conformational change, aggregation and intermolecular interactions. A combination of spectroscopic techniques, activity assays, small-angle X-ray scattering, and crystallography highlights that ILs, particularly their anions, bind to specific sites in the protein hydration layer via polar contacts on charged, polar and aromatic residues. The specific ion binding can induce more flexible loop regions in lysozyme, while the ion binding in the bulk phase can be more dynamic in solution. Overall, the protein behaviour in ILs depends on the net effect of nonspecific interactions and specific ion binding. Compared to formate, the nitrate anion induced high protein solubility, low activity, elongated shape and aggregation, which is largely owing to its higher propensity for ion binding. These findings provide new insights into protein-IL binding interactions and using ILs to modulate protein properties.
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Affiliation(s)
- Qi Han
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Yuyu Su
- School of Engineering, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Kate M Smith
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC 3168, Australia; Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, Villigen-PSI, 5232 Villigen, Switzerland
| | - Jack Binns
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
| | - Connie Darmanin
- La Trobe Institute for Molecular Science, Department of Mathematical and Physical Sciences, School of Computing Engineering and Mathematical Science, La Trobe University, Bundoora, VIC 3086, Australia.
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
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6
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Yadav N, Chahar D, Bisht M, Venkatesu P. Assessing the compatibility of choline-based deep eutectic solvents for the structural stability and activity of cellulase: Enzyme sustain at high temperature. Int J Biol Macromol 2023; 249:125988. [PMID: 37499720 DOI: 10.1016/j.ijbiomac.2023.125988] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/13/2023] [Accepted: 07/23/2023] [Indexed: 07/29/2023]
Abstract
As a new generation of 'green solvents' deep eutectic solvents (DESs) represents a promising alternative to the conventional solvents. Their environmental-benign nature and designer properties promote their utility in biocatalysis. Enzymes are marginally stable when exposed to physical/chemical disturbances. One such enzyme is cellulase which is a propitious catalyst for the depolymerization of cellulose under mild conditions. Therefore, their stability is a prerequisite condition to match demands of biorefineries. To address this issue of low stability, activity and thermal denaturation of cellulase, there is a need to find a sustainable and suitable co-solvent that is biocompatible with enzymes ultimately to facilitate their application in bio-industries. In this regard, we synthesized three choline-based DESs, choline chloride (ChCl)-glycerol, ChCl-ethylene glycol and ChCl-lactic acid and employed them to analyze their suitability for cellulase. The present study systematically evaluates the influence of the mentioned DESs on stability, activity and thermal stability of cellulase with the help of various spectroscopic techniques. The spectroscopic analysis revealed that the structural stability and activity of the enzyme were improved in presence of ChCl-glycerol and ChCl-ethylene glycol. The thermal stability was also very well maintained in both the DESs. Interestingly, the relative activity of cellulase was >80 % even after incubation at 50 °C after 48 h for both the DESs. This activity preservation behaviour was more pronounced for ChCl-ethylene glycol than ChCl-glycerol. Moreover, temperature variations studies also reveal promising results by maintain conformational intactness. On the other side, ChCl-lactic acid showed a deleterious effect on the enzyme both structurally as well as thermally. The dynamic light scattering (DLS) analysis provides more specific information about the negative influence of ChCl-lactic acid towards cellulase native structure. This DES induces unavoidable alterations in the enzyme structure which leads to the unfolding of enzyme, ultimately, destabilizing it. Overall, our results present a physical insight into how the enzyme stability and activity depend on the nature of DES. Also, the findings will help to facilitate the development and application of DESs as biocatalytic process.
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Affiliation(s)
- Niketa Yadav
- Department of Chemistry, University of Delhi, Delhi 110 007, India
| | - Deepak Chahar
- Department of Chemistry, University of Delhi, Delhi 110 007, India
| | - Meena Bisht
- Department of Chemistry, Sri Venkateswara College, University of Delhi, Delhi 110 007, India
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7
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Han Q, El Mohamad M, Brown S, Zhai J, Rosado CJ, Shen Y, Blanch EW, Drummond CJ, Greaves TL. Small angle X-ray scattering investigation of ionic liquid effect on the aggregation behavior of globular proteins. J Colloid Interface Sci 2023; 648:376-388. [PMID: 37302221 DOI: 10.1016/j.jcis.2023.05.130] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/02/2023] [Accepted: 05/18/2023] [Indexed: 06/13/2023]
Abstract
Globular proteins are well-folded model proteins, where ions can substantially influence their structure and aggregation. Ionic liquids (ILs) are salts in the liquid state with versatile ion combinations. Understanding the IL effect on protein behavior remains a major challenge. Here, we employed small angle X-ray scattering to investigate the effect of aqueous ILs on the structure and aggregation of globular proteins, namely, hen egg white lysozyme (Lys), human lysozyme (HLys), myoglobin (Mb), β-lactoglobulin (βLg), trypsin (Tryp) and superfolder green fluorescent protein (sfGFP). The ILs contain ammonium-based cations paired with the mesylate, acetate or nitrate anion. Results showed that only Lys was monomeric, whereas the other proteins formed small or large aggregates in buffer. Solutions with over 17 mol% IL resulted in significant changes in the protein structure and aggregation. The Lys structure was expanded at 1 mol% but compact at 17 mol% with structural changes in loop regions. HLys formed small aggregates, with the IL effect similar to Lys. Mb and βLg mostly had distinct monomer and dimer distributions depending on IL type and IL concentration. Complex aggregation was noted for Tryp and sfGFP. While the anion had the largest ion effect, changing the cation also induced the structural expansion and protein aggregation.
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Affiliation(s)
- Qi Han
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
| | - Mohamad El Mohamad
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Stuart Brown
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Jiali Zhai
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Carlos J Rosado
- Department of Diabetes, Central Clinical School, Monash University, VIC 3004, Australia; Department of Biochemistry, Monash University, VIC 3800, Australia
| | - Yi Shen
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia; The University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ewan W Blanch
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
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8
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Characterising a Protic Ionic Liquid Library with Applied Machine Learning Algorithms. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Biological activity, solvation properties and microstructuring of protic imidazolium ionic liquids. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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Li Z, Han Q, Wang K, Song S, Xue Y, Ji X, Zhai J, Huang Y, Zhang S. Ionic liquids as a tunable solvent and modifier for biocatalysis. CATALYSIS REVIEWS 2022. [DOI: 10.1080/01614940.2022.2074359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Zhuang Li
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Qi Han
- School of Science, STEM College, RMIT University, Melbourne, Victoria, Australia
| | - Kun Wang
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Shaoyu Song
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Yaju Xue
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Xiuling Ji
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
| | - Jiali Zhai
- School of Science, STEM College, RMIT University, Melbourne, Victoria, Australia
| | - Yuhong Huang
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Green Manufacture, CAS, Beijing, China
- Dalian National Laboratory for Clean Energy, CAS, Dalian, Liaoning, China
| | - Suojiang Zhang
- Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
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11
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Patel R, Clark AK, DeStefano G, DeStefano I, Gogoj H, Gray E, Patel AY, Hauner JT, Caputo GA, Vaden TD. Sequence-specific destabilization of azurin by tetramethylguanidinium-dipeptide ionic liquids. Biochem Biophys Rep 2022; 30:101242. [PMID: 35280523 PMCID: PMC8907678 DOI: 10.1016/j.bbrep.2022.101242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/18/2022] [Accepted: 03/02/2022] [Indexed: 12/01/2022] Open
Abstract
The thermal unfolding of the copper redox protein azurin was studied in the presence of four different dipeptide-based ionic liquids (ILs) utilizing tetramethylguanidinium as the cation. The four dipeptides have different sequences including the amino acids Ser and Asp: TMG-AspAsp, TMG-SerSer, TMG-SerAsp, and TMG-AspSer. Thermal unfolding curves generated from temperature-dependent fluorescence spectroscopy experiments showed that TMG-AspAsp and TMG-SerSer have minor destabilizing effects on the protein while TMG-AspSer and TMG-SerAsp strongly destabilize azurin. Red-shifted fluorescence signatures in the 25 °C correlate with the observed protein destabilization in the solutions with TMG-AspSer and TMG-SerAsp. These signals could correspond to interactions between the Asp residue in the dipeptide and the azurin Trp residue in the unfolded state. These results, supported by appropriate control experiments, suggest that dipeptide sequence-specific interactions lead to selective protein destabilization and motivate further studies of TMG-dipeptide ILs. Four different dipeptide-based ionic liquids were prepared with TMG as cation. The dipeptides included all four sequences containing Asp and Ser. The ionic liquids destabilizing effects on the protein azurin were measured. Different dipeptide sequences have different effects on the protein stability.
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Affiliation(s)
- Roshani Patel
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Austin K Clark
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Gabriella DeStefano
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Isabella DeStefano
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Hunter Gogoj
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Erin Gray
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Aashka Y Patel
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Joshua T Hauner
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Gregory A Caputo
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Timothy D Vaden
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
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12
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Han Q, Brown SJ, Drummond CJ, Greaves TL. Protein aggregation and crystallization with ionic liquids: Insights into the influence of solvent properties. J Colloid Interface Sci 2022; 608:1173-1190. [PMID: 34735853 DOI: 10.1016/j.jcis.2021.10.087] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022]
Abstract
Ionic liquids (ILs) have been used in solvents for proteins in many applications, including biotechnology, pharmaceutics, and medicine due to their tunable physicochemical and biological properties. Protein aggregation is often undesirable, and predominantly occurs during bioprocesses, while the aggregation process can be reversible or irreversible and the aggregates formed can be native/non-native and soluble/insoluble. Recent studies have clearly identified key properties of ILs and IL-water mixtures related to protein performance, suggesting the use of the tailorable properties of ILs to inhibit protein aggregation, to promote protein crystallization, and to control protein aggregation pathways. This review discusses the critical properties of IL and IL-water mixtures and presents the latest understanding of the protein aggregation pathways and the development of IL systems that affect or control the protein aggregation process. Through this feature article, we hope to inspire further advances in understanding and new approaches to controlling protein behavior to optimize bioprocesses.
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Affiliation(s)
- Qi Han
- School of Science, STEM College, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Stuart J Brown
- School of Science, STEM College, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
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13
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Protic Ionic Liquid Cation Alkyl Chain Length Effect on Lysozyme Structure. Molecules 2022; 27:molecules27030984. [PMID: 35164252 PMCID: PMC8839406 DOI: 10.3390/molecules27030984] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 11/16/2022] Open
Abstract
Solvents that stabilize protein structures can improve and expand their biochemical applications, particularly with the growing interest in biocatalytic-based processes. Aiming to select novel solvents for protein stabilization, we explored the effect of alkylammonium nitrate protic ionic liquids (PILs)-water mixtures with increasing cation alkyl chain length on lysozyme conformational stability. Four PILs were studied, that is, ethylammonium nitrate (EAN), butylammonium nitrate (BAN), hexylammonium nitrate (HAN), and octylammonium nitrate (OAN). The surface tension, viscosity, and density of PIL-water mixtures at low to high concentrations were firstly determined, which showed that an increasing cation alkyl chain length caused a decrease in the surface tension and density as well as an increase in viscosity for all PIL solutions. Small-angle X-ray scattering (SAXS) was used to investigate the liquid nanostructure of the PIL solutions, as well as the overall size, conformational flexibility and changes to lysozyme structure. The concentrated PILs with longer alkyl chain lengths, i.e., over 10 mol% butyl-, 5 mol% hexyl- and 1 mol% octylammonium cations, possessed liquid nanostructures. This detrimentally interfered with solvent subtraction, and the more structured PIL solutions prevented quantitative SAXS analysis of lysozyme structure. The radius of gyration (Rg) of lysozyme in the less structured aqueous PIL solutions showed little change with up to 10 mol% of PIL. Kratky plots, SREFLEX models, and FTIR data showed that the protein conformation was maintained at a low PIL concentration of 1 mol% and lower when compared with the buffer solution. However, 50 mol% EAN and 5 mol% HAN significantly increased the Rg of lysozyme, indicating unfolding and aggregation of lysozyme. The hydrophobic interaction and liquid nanostructure resulting from the increased cation alkyl chain length in HAN likely becomes critical. The impact of HAN and OAN, particularly at high concentrations, on lysozyme structure was further revealed by FTIR. This work highlights the negative effect of a long alkyl chain length and high concentration of PILs on lysozyme structural stability.
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Han Q, Binns J, Zhai J, Guo X, Ryan TM, Drummond CJ, Greaves TL. Insights on lysozyme aggregation in protic ionic liquid solvents by using small angle X-ray scattering and high throughput screening. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Bryant SJ, Brown SJ, Martin AV, Arunkumar R, Raju R, Elbourne A, Bryant G, Drummond CJ, Greaves TL. Cryopreservation of mammalian cells using protic ionic liquid solutions. J Colloid Interface Sci 2021; 603:491-500. [PMID: 34214724 DOI: 10.1016/j.jcis.2021.06.096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/02/2021] [Accepted: 06/15/2021] [Indexed: 02/08/2023]
Abstract
Cryopreservation has facilitated considerable advances in both medical technology and scientific research. However, further developments have been limited by the relatively low number of effective cryoprotective agents. Even after fifty years of research, most protocols rely on the same two toxic agents, i.e. dimethylsulfoxide or glycerol. Ionic liquids are a class of promising solvents which are known glass formers and may offer a less-toxic alternative. The research presented here investigates ten protic ionic liquids as potential cryoprotective agents. The liquids are screened for key properties including cellular toxicity, permeability and thermal behaviour. The most promising, ethylammonium acetate, was then tested as a cryoprotective agent on a model cell line and was found to be as effective as the common cryoprotectant, dimethylsulfoxide. This work reports the first use of a protic ionic liquid as an effective cryoprotective agent for a mammalian cell line. This will inform the development of a suite of potential new ionic liquid-based cryoprotectants that could potentially allow the cryopreservation of new cell types.
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Affiliation(s)
- Saffron J Bryant
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Stuart J Brown
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Andrew V Martin
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Radhika Arunkumar
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Rekha Raju
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Aaron Elbourne
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Gary Bryant
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Tamar L Greaves
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia.
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16
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Bryant SJ, Garcia A, Clarke RJ, Warr GG. Selective ion transport across a lipid bilayer in a protic ionic liquid. SOFT MATTER 2021; 17:2688-2694. [PMID: 33533359 DOI: 10.1039/d0sm02225j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ionic liquids (ILs) have exhibited enormous potential as electrolytes, designer solvents and reaction media, as well as being surprisingly effective platforms for amphiphile self-assembly and for preserving structure of complex biomolecules. This has led to their exploration as media for long-term biopreservation and in biosensors, for which their viability depends on their ability to sustain both structure and function within complex, multicomponent nanoscale compartments and assemblies. Here we show that a tethered lipid bilayer can be assembled directly in a purely IL environment that retains its structure upon exchange between IL and aqueous buffer, and that the membrane transporter valinomycin can be incorporated so as to retain its functionality and cation selectivity. This paves the way for the development of long-lived, non-aqueous microreactors and sensor assemblies, and demonstrates the potential for complex proteins to retain functionality in non-aqueous, ionic liquid solvents.
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Affiliation(s)
- Saffron J Bryant
- School of Chemistry, The University of Sydney, NSW 2006, Australia and School of Science, RMIT University, Melbourne, Victoria 3001, Australia.
| | - Alvaro Garcia
- School of Chemistry, The University of Sydney, NSW 2006, Australia and School of Life Sciences, University of Technology Sydney, NSW 2007, Australia
| | - Ronald J Clarke
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Gregory G Warr
- School of Chemistry, The University of Sydney, NSW 2006, Australia and University of Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
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17
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Behera K, Wani FA, Bhat AR, Juneja S, Banjare MK, Pandey S, Patel R. Behavior of lysozyme within ionic liquid-in-water microemulsions. J Mol Liq 2021; 326:115350. [DOI: https:/doi.org/10.1016/j.molliq.2021.115350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2023]
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18
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Behera K, Wani FA, Bhat AR, Juneja S, Banjare MK, Pandey S, Patel R. Behavior of lysozyme within ionic liquid-in-water microemulsions. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Han Q, Ryan TM, Rosado CJ, Drummond CJ, Greaves TL. Effect of ionic liquids on the fluorescence properties and aggregation of superfolder green fluorescence protein. J Colloid Interface Sci 2021; 591:96-105. [PMID: 33596505 DOI: 10.1016/j.jcis.2021.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/24/2021] [Accepted: 02/01/2021] [Indexed: 10/22/2022]
Abstract
Proteins generally tend to aggregate with less desirable properties in numerous solvents, which is one of the major challenges in the development of solvents for functional proteins. This work aims to utilize fluorescence spectroscopy and small angle X-ray scattering (SAXS) to understand the effects of ionic liquids (ILs) on the fluorescence and aggregation behavior of superfolder green fluorescent protein (sfGFP). The studied ILs consisted of four different anions coupled with primary, tertiary and quaternary ammonium cations. The results show that the chromophore fluorescence was generally maintained in 1 mol% IL-water mixtures, then decreased with increasing IL concentration. We primarily employed the pseudo-radius of gyration (pseudo-Rg) to evaluate sfGFP aggregation. The sfGFP was less aggregated with nitrate-based ILs compared to in buffer, and more aggregated in the mesylate-based ILs. Further, we show that the polyol additives of glycerol and glucose in IL-water mixtures slightly decreased the sfGFP propensity to aggregate. Size-exclusion chromatography (SEC)-SAXS was used to characterize the monomeric sfGFP in ethylammonium nitrate (EAN) and triethylammonium mesylate (TEAMs)-water mixtures. The presence of 1 mol% TEAMs maintained the sfGFP fluorescence, promoted the compact structure, but slightly increased the amount of large aggregates, which contrasted with that of EAN.
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Affiliation(s)
- Qi Han
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Timothy M Ryan
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Carlos J Rosado
- Department of Diabetes, Central Clinical School, Monash University, VIC 3004, Australia
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Tamar L Greaves
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
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20
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Patil KR, Patil SK, Shaikh VR, Dagade DH, Patil KJ. Studies of osmotic and activity coefficient properties of aqueous solutions of triethylammonium formate and triethylammonium glycolate protic ionic liquids at 298.15 K. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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21
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Antosiewicz JM, Długosz M. Constant-pH Brownian Dynamics Simulations of a Protein near a Charged Surface. ACS OMEGA 2020; 5:30282-30298. [PMID: 33251463 PMCID: PMC7689933 DOI: 10.1021/acsomega.0c04817] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/04/2020] [Indexed: 05/04/2023]
Abstract
We have developed a rigid-body Brownian dynamics algorithm that allows for simulations of a globular protein suspended in an ionic solution confined by a charged planar boundary, with an explicit treatment of pH-dependent protein protonation equilibria and their couplings to the electrostatic potential of the plane. Electrostatic interactions are described within a framework of the continuum Poisson-Boltzmann model, whereas protein-plane hydrodynamic interactions are evaluated based on analytical expressions for the position- and orientation-dependent near-wall friction tensor of a spheroid. The algorithm was applied to simulate near-surface diffusion of lysozyme in solutions having pH in the range 4-10 and ionic strengths of 10 and 150 mM. As a reference, we performed Brownian dynamics simulations in which the protein is assigned a fixed, most probable protonation state, appropriate for given solution conditions and unaffected by the presence of the charged plane, and Brownian dynamics simulations in which the protein probes possible protonation states with the pH-dependent probability, but these variations are not coupled to the electric field generated by the boundary. We show that electrostatic interactions with the negatively charged plane substantially modify probabilities of different protonation states of lysozyme and shift protonation equilibria of both acidic and basic amino acid side chains toward higher pH values. Consequently, equilibrium energy distributions, equilibrium position-orientation distributions, and functions that characterize rotational dynamics, which for a protein with multiple ionization sites, such as lysozyme, in the presence of a charged obstacle are pH-dependent, are significantly affected by the approach taken to incorporate the solution pH into simulations.
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22
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Abstract
With their ability to dissolve inorganic as well as organic materials, ionic
liquids have emerged as a versatile solvent system for a diverse range of organic
transformations. In the past few decades, the literature has witnessed remarkable advances
in a wide range of organic conversions carried out in the presence of various imidazolium,
pyridinium, pyrrolidinium, quinolinium and diazobicyclo-octane based ionic liquids. In
the reaction, ionic liquids serve as a solvent, catalyst or sometimes both. In certain cases,
they are also modified with metal nanoparticles or complexes to form heterogeneous
catalysts or are immobilized onto solid support like agar-agar to act as solid-support
catalysts. Reactions catalysed by ionic liquids incorporating chiral catalysts possess the
advantageous features of being highly enantioselective and reproducible, besides being
economical and easy to handle. In this review, an updated insight regarding the role played by ionic liquids in
various C-C bond-forming organic reactions, has been summarized.
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Affiliation(s)
- Mandeep Kaur
- Department of Chemistry, Sri Guru Granth Sahib World University, Fatehgarh Sahib (Pb), India
| | - Opinder Kaur
- Department of Chemistry, Sri Guru Granth Sahib World University, Fatehgarh Sahib (Pb), India
| | - Rahul Badru
- Department of Chemistry, Sri Guru Granth Sahib World University, Fatehgarh Sahib (Pb), India
| | - Sandeep Kaushal
- Department of Chemistry, Sri Guru Granth Sahib World University, Fatehgarh Sahib (Pb), India
| | - Pritpal Singh
- Department of Chemistry, Sri Guru Granth Sahib World University, Fatehgarh Sahib (Pb), India
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23
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Han Q, Smith KM, Darmanin C, Ryan TM, Drummond CJ, Greaves TL. Lysozyme conformational changes with ionic liquids: Spectroscopic, small angle x-ray scattering and crystallographic study. J Colloid Interface Sci 2020; 585:433-443. [PMID: 33109332 DOI: 10.1016/j.jcis.2020.10.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/19/2020] [Accepted: 10/07/2020] [Indexed: 01/14/2023]
Abstract
Solvents that support protein functionality are important for biochemical applications, and new solvents are required. Here we employ FTIR and fluorescence spectroscopies, small angle X-ray scattering (SAXS) and X-ray crystallography to understand conformational changes of lysozyme with ionic liquids (ILs) added. Spectroscopic techniques identified that the secondary structure of lysozyme was maintained at the lower IL concentrations of 1 and 5 mol%, though the Tryptophan environment was significantly altered with nitrate-based ILs present. SAXS experiments indicated that the radius of gyration of lysozyme increased with 1 mol% IL present, and then decreased with increasing IL concentrations. The tertiary structure, particularly the loop regions, changed as a function of IL concentration, and this depended on the IL type. The crystallographic structure of lysozyme with the IL of ethylammonium nitrate present confirmed the loop region was extended, and identified three specific binding sites with nitrate ions, and that the positively charged areas were IL sensitive regions. This work provides a detailed understanding of lysozyme conformational changes in the presence of ILs. This approach can be extended to other functionally-important proteins.
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Affiliation(s)
- Qi Han
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Kate M Smith
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC, 3168, Australia
| | - Connie Darmanin
- ARC Centre of Excellence in Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, VIC 3086, Australia
| | - Timothy M Ryan
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC, 3168, Australia
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia
| | - Tamar L Greaves
- School of Science, College of Science, Engineering and Health, RMIT University, 124 La Trobe Street, Melbourne, VIC 3000, Australia.
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24
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Christensen LFB, Nowak JS, Sønderby TV, Frank SA, Otzen DE. Quantitating denaturation by formic acid: imperfect repeats are essential to the stability of the functional amyloid protein FapC. J Biol Chem 2020; 295:13031-13046. [PMID: 32719003 PMCID: PMC7489911 DOI: 10.1074/jbc.ra120.013396] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/11/2020] [Indexed: 12/27/2022] Open
Abstract
Bacterial functional amyloids are evolutionarily optimized to aggregate, so much so that the extreme robustness of functional amyloid makes it very difficult to examine their structure-function relationships in a detailed manner. Previous work has shown that functional amyloids are resistant to conventional chemical denaturants, but they dissolve in formic acid (FA) at high concentrations. However, systematic investigation requires a quantitative analysis of FA's ability to denature proteins. Amyloid formed by Pseudomonas sp. protein FapC provides an excellent model to investigate FA denaturation. It contains three imperfect repeats, and stepwise removal of these repeats slows fibrillation and increases fragmentation during aggregation. However, the link to stability is unclear. We first calibrated FA denaturation using three small, globular, and acid-resistant proteins. This revealed a linear relationship between the concentration of FA and the free energy of unfolding with a slope of mFA+pH (the combined contribution of FA and FA-induced lowering of pH), as well as a robust correlation between protein size and mFA+pH We then measured the solubilization of fibrils formed from different FapC variants with varying numbers of repeats as a function of the concentration of FA. This revealed a decline in the number of residues driving amyloid formation upon deleting at least two repeats. The midpoint of denaturation declined with the removal of repeats. Complete removal of all repeats led to fibrils that were solubilized at FA concentrations 2-3 orders of magnitude lower than the repeat-containing variants, showing that at least one repeat is required for the stability of functional amyloid.
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Affiliation(s)
| | - Jan Stanislaw Nowak
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark
| | | | - Signe Andrea Frank
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark
| | - Daniel Erik Otzen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark.
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25
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Islam MM, Barik S, Preeyanka N, Sarkar M. Interaction of Lysozyme with Monocationic and Dicationic Ionic Liquids: Toward Finding a Suitable Medium for Biomacromolecules. J Phys Chem B 2020; 124:961-973. [DOI: 10.1021/acs.jpcb.9b10270] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mullah Muhaiminul Islam
- School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, HBNI, Bhimpur-Padanpur,
Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Sahadev Barik
- School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, HBNI, Bhimpur-Padanpur,
Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Naupada Preeyanka
- School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, HBNI, Bhimpur-Padanpur,
Jatni, Khurda, Bhubaneswar 752050, Odisha, India
| | - Moloy Sarkar
- School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, HBNI, Bhimpur-Padanpur,
Jatni, Khurda, Bhubaneswar 752050, Odisha, India
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26
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Kumar A, Bhakuni K, Venkatesu P. Strategic planning of proteins in ionic liquids: future solvents for the enhanced stability of proteins against multiple stresses. Phys Chem Chem Phys 2019; 21:23269-23282. [PMID: 31621726 DOI: 10.1039/c9cp04772g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ionic liquids (ILs) present a vast number of solvents capable of replacing toxic organic solvents in chemical, biotechnology and biomedical applications. ILs are inexpensive and environmentally friendly as the materials can be recycled conveniently. Chemists use a variety of cation and anion combinations to produce an IL that fits the requirements of the sustainable future through the pursuit of greener chemical processes. As such, the development of various types of ILs has been recognized as the emergence of environmentally friendly solvents to attain enhanced protein stability in vitro. The literature survey reveals that there exist a large number of scholarly articles as well as elegant reviews on protein stability in ILs. Biomolecules have adapted to antagonistic environmental stresses that normally denature proteins, and the mechanism of adaptation that protects the cellular components against denaturation involves the intracellular concentration of co-solvents. In this regard, recent experimental results distinctly demonstrated that ILs are stabilizing proteins against denaturing stresses, and their presence in the cells does not alter protein functional activities. However, a review focusing particularly on the refolding and counteracting effects of the ILs against denatured proteins by multiple stresses is still missing. This perspective unveils the studies that have been conducted to improve protein stabilities with ILs as well as the refolding and counteracting abilities of these ILs against the denatured proteins under the influence of multiple stresses. We believe that ILs can provide significant environmental and economic advantages for biochemical processes in the near future. Essentially, numerous investigations are required to allow us to further explore the stabilizing properties of ILs over proteins.
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Affiliation(s)
- Awanish Kumar
- Department of Chemistry, University of Delhi, Delhi-110 007, India.
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27
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Thermodynamic studies of aqueous solutions of ammonium based nitrate protic ionic liquids at different temperatures (288.15 K to 303.15 K) and 101.325 kPa: A volumetric approach. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.110884] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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28
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Schindl A, Hagen ML, Muzammal S, Gunasekera HAD, Croft AK. Proteins in Ionic Liquids: Reactions, Applications, and Futures. Front Chem 2019; 7:347. [PMID: 31179267 PMCID: PMC6543490 DOI: 10.3389/fchem.2019.00347] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/26/2019] [Indexed: 01/01/2023] Open
Abstract
Biopolymer processing and handling is greatly facilitated by the use of ionic liquids, given the increased solubility, and in some cases, structural stability imparted to these molecules. Focussing on proteins, we highlight here not just the key drivers behind protein-ionic liquid interactions that facilitate these functionalities, but address relevant current and potential applications of protein-ionic liquid interactions, including areas of future interest.
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Affiliation(s)
- Alexandra Schindl
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Faculty of Medicine & Health Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
- Faculty of Science, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
| | - Matthew L. Hagen
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Centre for Additive Manufacturing, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Shafaq Muzammal
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Henadira A. D. Gunasekera
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Centre for Additive Manufacturing, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Anna K. Croft
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
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29
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Yalcin D, Drummond CJ, Greaves TL. High throughput approach to investigating ternary solvents of aqueous non-stoichiometric protic ionic liquids. Phys Chem Chem Phys 2019; 21:6810-6827. [PMID: 30534703 DOI: 10.1039/c8cp05894f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of ionic liquids (ILs) is limited for many applications due to their cost and/or viscosity. An efficient solution is to make mixtures of ILs with molecular solvents. However, it is well known that there are a large number of possible cation and anion combinations resulting in ILs, and this becomes a vast number when these are then combined with a molecular solvent. Therefore, we need structure-property relationships to design new IL-molecular solvent systems. In this work we have applied high throughput methods to investigate IL containing solutions to provide systematic data of a broad compositional space. We have principally focused on the surface tension, apparent pH and liquid nanostructure to identify potential self-assembly and protein stabilizing ability of solvent systems. Non-stoichiometric and aqueous IL-solvents were prepared in a high-throughput manner based on a deliberate experimental design approach such that 26 samples were prepared for each cation-anion-water combination. A selection of 8 protic ionic liquids (PILs) were used as starting materials, comprising ethanol-, ethyl-, butyl-, and pentylammonium cations combined with formate, acetate and nitrate anions. This resulted in a total of 208 different solvent systems. The measured solvent properties showed different trends in base-rich and acid-rich solvent combinations. Surface tensions of base-rich samples exhibited a relatively linear relationship with increasing excess amine, while acid-rich samples were more dominantly affected by the change in water content. Liquid nanostructure of acid-rich samples was retained upon water dilution, whereas a significant SAXS peak shift towards lower scattering angles was observed in the presence of excess amines, indicating larger nanosized aggregates were forming. The design of experiment approach used here is considered to be applicable to any multi-component solvent compositional space due to its suitability in using small data sets to cover large compositional spaces, and hence can be employed to decrease the time and sample quantities required.
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Affiliation(s)
- Dilek Yalcin
- School of Science, College of Science, Engineering and Health, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia.
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30
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Arunkumar R, Drummond CJ, Greaves TL. FTIR Spectroscopic Study of the Secondary Structure of Globular Proteins in Aqueous Protic Ionic Liquids. Front Chem 2019; 7:74. [PMID: 30815435 PMCID: PMC6381012 DOI: 10.3389/fchem.2019.00074] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/28/2019] [Indexed: 11/13/2022] Open
Abstract
Protein misfolding is a detrimental effect which can lead to the inactivation of enzymes, aggregation, and the formation of insoluble protein fibrils called Amyloids. Consequently, it is important to understand the mechanism of protein folding, and under which conditions it can be avoided or mitigated. Ionic liquids (ILs) have previously been shown as capable of increasing or decreasing protein stability, depending on the specific IL, IL concentration and which protein. However, a greater range of IL-proteins need to be systematically explored to enable the development of structure-property relationships. In this work, the secondary structure of four proteins, lysozyme, trypsin, β-lactoglobulin and α-amylase, were studied in aqueous solutions of 10 protic ionic liquids (PILs) with 0-50 mol% PIL present. The PILs consisted of ethyl-, ethanol-, diethanol- and triethanolammonium cations paired with nitrate, formate, acetate or glycolate anions. The secondary structure was obtained using ATR-FTIR spectroscopy. It was found that lysozyme and trypsin retained its secondary structure, consistent with a native folded state, for many of the aqueous IL solutions which contained a formate or nitrate anion at the most dilute concentrations. In contrast, α-amylase and β-lactoglobulin generally had poor stability and solubility in the IL solutions. This may be due to the isoelectric point of α-amylase and β-lactoglobulin being closer to the pH of the solvents. All four proteins were insoluble in ethyl-, ethanol- and diethanolammonium acetate, though α-amylase and trypsin retained their secondary structure in up to 20 and 30 mol% of triethanolammonium acetate, respectively. It was evident that the protein stability varied substantially depending on the protein-IL combination, and the IL concentration in water. Overall, the findings indicated that some ions and some ILs were in general better for protein solubility and stability than others, such as acetate leading to poor solubility, and EAN and EAF generally leading to better protein stability than the other PILs. This study of four proteins in 10 aqueous PILs clearly showed that there are many complexities in their interactions and no clear general trend, despite the similarities between the PIL structures. This highlights the need for more and larger studies to enable the selection and optimization of PIL solvents used with biomolecules.
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Affiliation(s)
| | | | - Tamar L. Greaves
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC, Australia
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Egorova KS, Ananikov VP. Fundamental importance of ionic interactions in the liquid phase: A review of recent studies of ionic liquids in biomedical and pharmaceutical applications. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.09.025] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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32
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Kumari M, Singh UK, Beg I, Alanazi AM, Khan AA, Patel R. Effect of cations and anions of ionic liquids on the stability and activity of lysozyme: Concentration and temperature effect. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.09.075] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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33
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Perkin S, Kirchner B, Fayer MD. Preface: Special Topic on Chemical Physics of Ionic Liquids. J Chem Phys 2018; 148:193501. [DOI: 10.1063/1.5039492] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Susan Perkin
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, Universität Bonn, Beringstr. 4, D-53115 Bonn, Germany
| | - Michael D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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