201
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Gault S, Cockell CS. Perchlorate Salts Exert a Dominant, Deleterious Effect on the Structure, Stability, and Activity of α-Chymotrypsin. ASTROBIOLOGY 2021; 21:405-412. [PMID: 33784200 DOI: 10.1089/ast.2020.2223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The presence of perchlorate ions on Mars raises the question of how these ions influence the biochemistry of any contaminant life introduced into the martian environment, or what selection pressures perchlorate ions exert on any environment that contains these ions, such as the Atacama Desert. In this study, we investigated the structure, stability, and enzyme activity of the model enzyme α-chymotrypsin in the presence of five Mars relevant salts, MgSO4, MgCl2, Mg(ClO4)2, Ca(ClO4)2, and NaClO4. We found that all the perchlorate salts reduced the enzyme activity of α-chymotrypsin in a concentration-dependent manner, with Mg(ClO4)2 and Ca(ClO4)2 having the greatest effect. This observation extends to our structural studies, which show that 1 M Mg(ClO4)2 and Ca(ClO4)2 greatly alter the tertiary structural environment of α-chymotrypsin. We also found that all the perchlorate salts assayed reduced the melting temperature of α-chymotrypsin, whereas the sulfate and chloride salts were able to increase the protein melting temperature. We also demonstrated that a brine containing both perchlorate and sulfate ions exerts the same deleterious effects on α-chymotrypsin's melting temperature and enzyme activity as that of a perchlorate-only brine. This suggests that the perchlorate salts exert a dominant, deleterious effect on protein biochemistry. These results indicate that although perchlorate salts are beneficial to the presence of liquid water due to low eutectic points, they also hamper the habitability of their own environment. Life in such brines would, therefore, have to adapt its cellular machinery to the perchlorate ion's presence or find a way of excluding it from said machinery.
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Affiliation(s)
- Stewart Gault
- Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Charles S Cockell
- Centre for Astrobiology, SUPA School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
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202
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Kobrak MN, Nykypanchuk D, Janssen CHC. Relationship between liquid nanoscale structure in solvents and the strength of the Hofmeister effect in extraction experiments. Phys Chem Chem Phys 2021; 23:6266-6277. [PMID: 33735349 DOI: 10.1039/d0cp05973k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we used mixtures of carboxylic acids and amines as solvents for the liquid-liquid extraction of copper salts with various anions from aqueous phase, and systematically varied the acid/amine ratio to determine its influence on extraction efficiency. The organic phases resulting from these extraction experiments were studied using small-angle X-ray scattering (SAXS), establishing a connection between the extraction process and the liquid structure. A relationship is found between the extent of extraction for the metal salt, the strength of the Hofmeister effect of the anions of the salt, and the characteristic lengthscale of the observed liquid nanoscale structure before and after extraction.
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Affiliation(s)
- Mark N Kobrak
- Department of Chemistry, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210, USA and Department of Chemistry, Graduate Center of the City University of New York, 365 Fifth Ave., New York, NY 10016, USA
| | - Dmytro Nykypanchuk
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Camiel H C Janssen
- Departamento de Ingeniería Química, Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Coyoacán, Cd. Universitaria, 04510 Ciudad de México, Mexico.
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203
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Abranches DO, Benfica J, Soares BP, Ferreira AM, Sintra TE, Shimizu S, Coutinho JAP. The impact of the counterion in the performance of ionic hydrotropes. Chem Commun (Camb) 2021; 57:2951-2954. [PMID: 33621286 DOI: 10.1039/d0cc08092f] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The efficiency of an ionic hydrotrope is shown to increase with the hydrophobicity of its counterion, challenging the common view that ionic hydrotropes should possess a small, densely charged counterion such as sodium or chloride.
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Affiliation(s)
- Dinis O Abranches
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Jordana Benfica
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Bruna P Soares
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Ana M Ferreira
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Tânia E Sintra
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Seishi Shimizu
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
| | - João A P Coutinho
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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204
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Tutol JN, Lee J, Chi H, Faizuddin FN, Abeyrathna SS, Zhou Q, Morcos F, Meloni G, Dodani SC. A single point mutation converts a proton-pumping rhodopsin into a red-shifted, turn-on fluorescent sensor for chloride. Chem Sci 2021; 12:5655-5663. [PMID: 34163777 PMCID: PMC8179538 DOI: 10.1039/d0sc06061e] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
The visualization of chloride in living cells with fluorescent sensors is linked to our ability to design hosts that can overcome the energetic penalty of desolvation to bind chloride in water. Fluorescent proteins can be used as biological supramolecular hosts to address this fundamental challenge. Here, we showcase the power of protein engineering to convert the fluorescent proton-pumping rhodopsin GR from Gloeobacter violaceus into GR1, a red-shifted, turn-on fluorescent sensor for chloride in detergent micelles and in live Escherichia coli. This non-natural function was unlocked by mutating D121, which serves as the counterion to the protonated retinylidene Schiff base chromophore. Substitution from aspartate to valine at this position (D121V) creates a binding site for chloride. The binding of chloride tunes the pK a of the chromophore towards the protonated, fluorescent state to generate a pH-dependent response. Moreover, ion pumping assays combined with bulk fluorescence and single-cell fluorescence microscopy experiments with E. coli, expressing a GR1 fusion with a cyan fluorescent protein, show that GR1 does not pump ions nor sense membrane potential but instead provides a reversible, ratiometric readout of changes in extracellular chloride at the membrane. This discovery sets the stage to use natural and laboratory-guided evolution to build a family of rhodopsin-based fluorescent chloride sensors with improved properties for cellular applications and learn how proteins can evolve and adapt to bind anions in water.
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Affiliation(s)
- Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Jessica Lee
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Hsichuan Chi
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Farah N Faizuddin
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Qin Zhou
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Faruck Morcos
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Bioengineering, The University of Texas at Dallas Richardson TX 75080 USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
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205
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Ashraf H, Guo Y, Wang N, Pang S, Zhang YH. Hygroscopicity of Hofmeister Salts and Glycine Aerosols-Salt Specific Interactions. J Phys Chem A 2021; 125:1589-1597. [PMID: 33576639 DOI: 10.1021/acs.jpca.0c10710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Hofmeister effect of inorganic ions to precipitate proteins has been used to understand the coagulation phenomenon in colloid and protein science. Herein, for the first time, this effect is studied on the hygroscopicity of aerosols using ATR-FTIR spectroscopy. The representative Hofmeister salts (MgSO4, KCl, NH4NO3) and amino acid (glycine) with different amino acid/salt molar ratios (ASRs) are mixed and atomized into micrometer-sized particles. For mixed kosmotrope (MgSO4)/glycine and chaotrope (NH4NO3)/glycine with an ASR of 1:1, both ERHs (efflorescence relative humidities) and DRHs (deliquescence relative humidities) are absent. However, for the mixtures of glycine and neutral salt (KCl), no DRH is observed while 66.2 and 61.4% ERH of glycine is detected for mixtures with ASRs of 1:1 and 1:3, respectively, which is similar to pure glycine. For the mixture of NH4NO3/glycine with an ASR of 1:3, ERH and DRH are found to be 15.4 and 32.2% RH, less than that of pure NH4NO3. Further, interactions between glycine-salt and/or water is also studied in the mixtures during hydration and dehydration. Water-mediated ion-glycine interaction is detected based on the two glycine bands merging into one band. Glycine-SO42- interaction is present for glycine/sulfate in all ASRs, while glycine-NO3- interaction is only seen for 1:3 glycine/NH4NO3 mixtures during hydration. This work opens a window to understand the Hofmeister effect on the hygroscopicity of atmospheric aerosols.
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Affiliation(s)
- Hamad Ashraf
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P R China
| | - Yaxin Guo
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P R China
| | - Na Wang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P R China
| | - Shufeng Pang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P R China
| | - Yun-Hong Zhang
- The Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P R China
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206
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Hpone Myint K, Ding W, Willard AP. The Influence of Spectator Cations on Solvent Reorganization Energy Is a Short-Range Effect. J Phys Chem B 2021; 125:1429-1438. [PMID: 33525875 DOI: 10.1021/acs.jpcb.0c09895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this manuscript, we use classical molecular dynamics simulation to explore the origin of specific cation effects on the rates of bulk-phase aqueous electron transfer (ET) reactions. We consider 0.6 M solutions of Cl- and a series of different cations: Li+, Na+, K+, Rb+, and Cs+. We evaluate the collective electrostatic fluctuations that drive Marcus-like ET and find that they are essentially unaffected by changes in the cationic species. This finding implies that the structure making/breaking properties of various cations do not exert a significant influence on bulk-phase ET reactions. We evaluate the role of ion pairing in these specific cation effects and find, unsurprisingly, that model redox anions that are more highly charged tend to pair more effectively with spectator cations than their monovalent counterparts. We demonstrate that this ion pairing significantly affects local electrostatic fluctuations for the anionic redox species and thus conclude that ion pairing is one of the likely sources of rate-dependent cation effects in aqueous ET reactions.
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Affiliation(s)
- Kyaw Hpone Myint
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Wendu Ding
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Adam P Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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207
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Savastano M. Words in supramolecular chemistry: the ineffable advances of polyiodide chemistry. Dalton Trans 2021; 50:1142-1165. [PMID: 33496303 DOI: 10.1039/d0dt04091f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Polyiodide chemistry has a rich history deeply intertwined with the development of supramolecular chemistry. Technological and theoretical interest in polyiodides has not diminished in the last decade, quite the contrary; yet the advances this perspective intends to cover are muddled by the involution of supramolecular vocabulary, preventing their unbiased discussion. Herein we discuss the pressing necessity of ordering the current babel of novel - and less so - supramolecular terms. Shared decisions at the community level might be required to shape the field into a harmonious body of knowledge, dominated by concepts rather than words. Secondary, σ-hole and halogen bonding schools of thought are all addressed here, together with their respective impact on the field. Then, on the basis of a shared vocabulary, a discussion of polyiodide chemistry is presented, starting with a revisited view of triiodide. The contemporary fields of supramolecular caging and polyiodide networks are then discussed, with emphasis on how the terms we choose to use deeply affect scientific progress.
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Affiliation(s)
- Matteo Savastano
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Italy.
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208
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Li D, Wang H, Li C, Liang Y, Yan X, Zhang H. Determination and modulation of the typical interactions among dispersed phases relevant to flotation applications: A review. Adv Colloid Interface Sci 2021; 288:102359. [PMID: 33422930 DOI: 10.1016/j.cis.2020.102359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/04/2020] [Accepted: 12/24/2020] [Indexed: 11/28/2022]
Abstract
Flotation is a process involving multi-components, multi-scales, and gas-liquid-solid three phases, where the material separation is achieved based on the difference in surface hydrophobicity of various constituents. In a flotation system, fluids are usually regarded as the continuous phase, while the dispersed phases refer to scattered particles, bubbles, and droplets with low solubility as a dispersion that is surrounded by the aqueous environment. Fundamentally, the interactions among dispersed phases exist throughout the flotation process, and play distinct roles during different periods. For example, the liquid collector-solid, solid-solid, bubble-bubble and gas bubble-solid interactions are closely associated with the particle surface modification, particle behavior, bubble size evolution and separation in flotation, respectively. Therefore, the influences of each stage are all worthy of concern, and should be spared sufficient attention, which requires to formulate a horizontal writing structure. In this review, instead of summarizing all available characterization techniques or measurements, certain typical examples or methods were consciously chosen to perform analysis or comparison, aiming to summarize recent studies on the determination and modulation of dispersed phase interactions. The determination on the interactions among dispersed phases is helpful for fundamentally understanding the microcosmic process connotations, and their modulation contributes to firmly providing macroscopic optimization schemes for practical applications. By integrating some typically available theoretical calculations and experimental measurements related to the dispersed phase interactions, the present article is devoted to revealing the influential factors, finding out the current challenges or knowledge gaps, and affording certain references or suggestions for future investigations.
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Affiliation(s)
- Danlong Li
- National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, 221116 Xuzhou, China; School of Chemical Engineering and Technology, China University of Mining and Technology, 221116 Xuzhou, China
| | - Hainan Wang
- National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, 221116 Xuzhou, China; School of Chemical Engineering and Technology, China University of Mining and Technology, 221116 Xuzhou, China
| | - Chenwei Li
- National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, 221116 Xuzhou, China; School of Chemical Engineering and Technology, China University of Mining and Technology, 221116 Xuzhou, China
| | - Yannan Liang
- National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, 221116 Xuzhou, China; School of Chemical Engineering and Technology, China University of Mining and Technology, 221116 Xuzhou, China
| | - Xiaokang Yan
- National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, 221116 Xuzhou, China; School of Chemical Engineering and Technology, China University of Mining and Technology, 221116 Xuzhou, China
| | - Haijun Zhang
- National Engineering Research Center for Coal Preparation and Purification, China University of Mining and Technology, 221116 Xuzhou, China; School of Chemical Engineering and Technology, China University of Mining and Technology, 221116 Xuzhou, China.
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209
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de Oliveira DM, Bredt AJ, Miller TC, Corcelli SA, Ben-Amotz D. Spectroscopic and Structural Characterization of Water-Shared Ion-Pairs in Aqueous Sodium and Lithium Hydroxide. J Phys Chem B 2021; 125:1439-1446. [PMID: 33512171 DOI: 10.1021/acs.jpcb.0c10564] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Aria J. Bredt
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tierney C. Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Steven A. Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Dor Ben-Amotz
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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210
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Denz M, Marschall M, Herrmann H, Köster S. Ion type and valency differentially drive vimentin tetramers into intermediate filaments or higher order assemblies. SOFT MATTER 2021; 17:870-878. [PMID: 33237065 DOI: 10.1039/d0sm01659d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Vimentin intermediate filaments, together with actin filaments and microtubules, constitute the cytoskeleton in cells of mesenchymal origin. The mechanical properties of the filaments themselves are encoded in their molecular architecture and depend on their ionic environment. It is thus of great interest to disentangle the influence of both the ion type and their concentration on vimentin assembly. We combine small angle X-ray scattering and fluorescence microscopy and show that vimentin in the presence of the monovalent ions, K+ and Na+, assembles into "standard filaments" with a radius of about 6 nm and 32 monomers per cross-section. In contrast, di- and multivalent ions, independent of type and valency, lead to the formation of thicker filaments associating over time into higher order structures. Hence, our results may indeed be of relevance for living cells, as local ion concentrations in the cytoplasm during certain physiological activities may differ considerably from average intracellular concentrations.
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Affiliation(s)
- Manuela Denz
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
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211
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Koteshwara A, Philip NV, Aranjani JM, Hariharapura RC, Volety Mallikarjuna S. A set of simple methods for detection and extraction of laminarinase. Sci Rep 2021; 11:2489. [PMID: 33510321 PMCID: PMC7844030 DOI: 10.1038/s41598-021-81807-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/04/2020] [Indexed: 11/08/2022] Open
Abstract
A carefully designed ammonium sulfate precipitation will simplify extraction of proteins and is considered to be a gold standard among various precipitation methods. Therefore, optimization of ammonium sulfate precipitation can be an important functional step in protein purification. The presence of high amounts of ammonium sulphate precludes direct detection of many enzymatically active proteins including reducing sugar assays (e.g. Nelson-Somogyi, Reissig and 3,5-dinitrosalicylic acid methods) for assessing carbohydrases (e.g. laminarinase (β (1-3)-glucanohydrolase), cellulases and chitinases). In this study, a simple method was developed using laminarin infused agarose plate for the direct analysis of the ammonium sulphate precipitates from Streptomyces rimosus AFM-1. The developed method is simple and convenient that can give accurate results even in presence of ammonium sulfate in the crude precipitates. Laminarin is a translucent substrate requiring the use of a stain to visualize the zones of hydrolysis in a plate assay. A very low-cost and locally available fluorescent optical fabric brightener Tinopal CBS-X has been used as a stain to detect the zones of hydrolysis. We also report simple methods to prepare colloidal chitin and cell free supernatant in this manuscript.
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Affiliation(s)
- Ananthamurthy Koteshwara
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Udupi, Karnataka, 576104, India
| | - Nancy V Philip
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Udupi, Karnataka, 576104, India
| | - Jesil Mathew Aranjani
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Udupi, Karnataka, 576104, India
| | - Raghu Chandrashekhar Hariharapura
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Udupi, Karnataka, 576104, India
| | - Subrahmanyam Volety Mallikarjuna
- Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Udupi, Karnataka, 576104, India.
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212
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Suematsu A, Akiyama R. Solvent effect for an effective attraction between like-charged macroions immersed in an electrolyte solution: The intensification mechanism of the effective attraction caused by the translational motion of solvent particles. J Chem Phys 2021; 154:034902. [PMID: 33499638 DOI: 10.1063/5.0033874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The effective interaction between macroanions immersed in an electrolyte solution was calculated using an integral equation theory of liquids to study the solvent granularity effect on the effective attraction mediated by cations. Explicit and implicit solvent models were examined. The effective attraction for the explicit solvent model was found to be stronger than that for the implicit solvent model. This solvent effect was remarkably enhanced only when the effective attraction between macroanions was strong; this means that the solvent effect is not a usual excluded volume effect. The intensification mechanism of the attraction by the solvent granularity is analyzed in the present study, and an indirect mechanism is proposed.
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Affiliation(s)
- Ayumi Suematsu
- Faculty of Science and Engineering, Kyushu Sangyo University, Fukuoka 813-8503, Japan
| | - Ryo Akiyama
- Department of Chemistry, Kyushu University, Fukuoka 812-0395, Japan
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213
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Friesen S, Fedotova MV, Kruchinin SE, Buchner R. Hydration and dynamics of L-glutamate ion in aqueous solution. Phys Chem Chem Phys 2021; 23:1590-1600. [PMID: 33409510 DOI: 10.1039/d0cp05489e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Aqueous solutions of sodium l-glutamate (NaGlu) in the concentration range 0 < c/M ≤ 1.90 at 25 °C were investigated by dielectric relaxation spectroscopy (DRS) and statistical mechanics (1D-RISM and 3D-RISM calculations) to study the hydration and dynamics of the l-glutamate (Glu-) anion. Although at c → 0 water molecules beyond the first hydration shell are dynamically affected, Glu- hydration is rather fragile and for c ⪆ 0.3 M apparently restricted to H2O molecules hydrogen bonding to the carboxylate groups. These hydrating dipoles are roughly parallel to the anion moment, leading to a significantly enhanced effective dipole moment of Glu-. However, l-glutamate dynamics is determined by the rotational diffusion of individual anions under hydrodynamic slip boundary conditions. Thus, the lifetime of the hydrate complexes, as well as of possibly formed [Na+Glu-]0 ionpairs and l-glutamate aggregates, cannot exceed the characteristic timescale for Glu- rotation.
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Affiliation(s)
- Sergej Friesen
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Marina V Fedotova
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya St. 1, 153045 Ivanovo, Russian Federation.
| | - Sergey E Kruchinin
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya St. 1, 153045 Ivanovo, Russian Federation.
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
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214
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Bruce EE, Bui PT, Cao M, Cremer PS, van der Vegt NFA. Contact Ion Pairs in the Bulk Affect Anion Interactions with Poly( N-isopropylacrylamide). J Phys Chem B 2021; 125:680-688. [PMID: 33406822 DOI: 10.1021/acs.jpcb.0c11076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Salt effects on the solubility of uncharged polymers in aqueous solutions are usually dominated by anions, while the role of the cation with which they are paired is often ignored. In this study, we examine the influence of three aqueous metal iodide salt solutions (LiI, NaI, and CsI) on the phase transition temperature of poly(N-isopropylacrylamide) (PNIPAM) by measuring the turbidity change of the solutions. Weakly hydrated anions, such as iodide, are known to interact with the polymer and thereby lead to salting-in behavior at low salt concentration followed by salting-out behavior at higher salt concentration. When varying the cation type, an unexpected salting-out trend is observed at higher salt concentrations, Cs+ > Na+ > Li+. Using molecular dynamics simulations, it is demonstrated that this originates from contact ion pair formation in the bulk solution, which introduces a competition for iodide ions between the polymer and cations. The weakly hydrated cation, Cs+, forms contact ion pairs with I- in the bulk solution, leading to depletion of CsI from the polymer-water interface. Microscopically, this is correlated with the repulsion of iodide ions from the amide moiety.
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Affiliation(s)
- Ellen E Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Pho T Bui
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mengrui Cao
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
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215
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Patel AY, Jonnalagadda KS, Paradis N, Vaden TD, Wu C, Caputo GA. Effects of Ionic Liquids on Metalloproteins. Molecules 2021; 26:514. [PMID: 33478102 PMCID: PMC7835893 DOI: 10.3390/molecules26020514] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/04/2021] [Accepted: 01/08/2021] [Indexed: 01/28/2023] Open
Abstract
In the past decade, innovative protein therapies and bio-similar industries have grown rapidly. Additionally, ionic liquids (ILs) have been an area of great interest and rapid development in industrial processes over a similar timeline. Therefore, there is a pressing need to understand the structure and function of proteins in novel environments with ILs. Understanding the short-term and long-term stability of protein molecules in IL formulations will be key to using ILs for protein technologies. Similarly, ILs have been investigated as part of therapeutic delivery systems and implicated in numerous studies in which ILs impact the activity and/or stability of protein molecules. Notably, many of the proteins used in industrial applications are involved in redox chemistry, and thus often contain metal ions or metal-associated cofactors. In this review article, we focus on the current understanding of protein structure-function relationship in the presence of ILs, specifically focusing on the effect of ILs on metal containing proteins.
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Affiliation(s)
- Aashka Y. Patel
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; (A.Y.P.); (N.P.); (T.D.V.); (C.W.)
| | | | - Nicholas Paradis
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; (A.Y.P.); (N.P.); (T.D.V.); (C.W.)
| | - Timothy D. Vaden
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; (A.Y.P.); (N.P.); (T.D.V.); (C.W.)
| | - Chun Wu
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; (A.Y.P.); (N.P.); (T.D.V.); (C.W.)
- Department of Molecular and Cellular Biosciences, Rowan University, Glassboro, NJ 08028, USA
| | - Gregory A. Caputo
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; (A.Y.P.); (N.P.); (T.D.V.); (C.W.)
- Department of Molecular and Cellular Biosciences, Rowan University, Glassboro, NJ 08028, USA
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216
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Yamashita M, Ing CE, Yeung PSW, Maneshi MM, Pomès R, Prakriya M. The basic residues in the Orai1 channel inner pore promote opening of the outer hydrophobic gate. J Gen Physiol 2021; 152:132615. [PMID: 31816637 PMCID: PMC7034092 DOI: 10.1085/jgp.201912397] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/25/2019] [Accepted: 11/05/2019] [Indexed: 12/12/2022] Open
Abstract
CRAC channels contain a cluster of positively charged residues in the inner pore whose function is not understood. Here, we show that these positive charges promote pore opening by enhancing hydration of the hydrophobic gate located at the outer end of the pore. Store-operated Orai1 channels regulate a wide range of cellular functions from gene expression to cell proliferation. Previous studies have shown that gating of Orai1 channels is regulated by the outer pore residues V102 and F99, which together function as a hydrophobic gate to block ion conduction in resting channels. Opening of this gate occurs through a conformational change that moves F99 away from the permeation pathway, leading to pore hydration and ion conduction. In addition to this outer hydrophobic gate, several studies have postulated the presence of an inner gate formed by the basic residues R91, K87, and R83 in the inner pore. These positively charged residues were suggested to block ion conduction in closed channels via mechanisms involving either electrostatic repulsion or steric occlusion by a bound anion plug. However, in contrast to this model, here we find that neutralization of the basic residues dose-dependently abolishes both STIM1-mediated and STIM1-independent activation of Orai1 channels. Molecular dynamics simulations show that loss of the basic residues dehydrates the pore around the hydrophobic gate and stabilizes the pore in a closed configuration. Likewise, the severe combined immunodeficiency mutation, Orai1 R91W, closes the channel by dewetting the hydrophobic stretch of the pore and stabilizing F99 in a pore-facing configuration. Loss of STIM1-gating in R91W and in the other basic residue mutants is rescued by a V102A mutation, which restores pore hydration at the hydrophobic gate to repermit ion conduction. These results indicate that the inner pore basic residues facilitate opening of the principal outer hydrophobic gate through a long-range effect involving hydration of the outer pore.
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Affiliation(s)
- Megumi Yamashita
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL
| | - Christopher E Ing
- Molecular Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Priscilla See-Wai Yeung
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL
| | - Mohammad M Maneshi
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL
| | - Régis Pomès
- Molecular Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL
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217
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Borkowski AK, Piskulich ZA, Thompson WH. Examining the Hofmeister Series through Activation Energies: Water Diffusion in Aqueous Alkali-Halide Solutions. J Phys Chem B 2021; 125:350-359. [PMID: 33382267 DOI: 10.1021/acs.jpcb.0c09965] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of ions on the properties of aqueous solutions is often categorized in terms of the Hofmeister series that ranks them from chaotropes ("structure-breakers"), which weaken the surrounding hydrogen-bond network to kosmotropes ("structure-makers"), which enhance it. Here, we investigate the Hofmeister series in ∼1 M sodium-halide solutions using molecular dynamics simulations to calculate the effect of the identity and proximity of the halide anion on both the water diffusion coefficient and its activation energy. A recently developed method for calculating the activation energy from a single-temperature simulation is used, which also permits a rigorous decomposition into contributions from different interactions and motions. The mechanisms of the salt effects on the water dynamics are explored by separately considering water molecules based on their location relative to the ions. The results show that water diffusion is accelerated moving down the halide group from F- to I-. The behavior of the diffusion activation energy, Ea, is more complex, indicating a significant role for entropic effects. However, water molecules in the first or second solvation shell of an ion exhibit a decrease in Ea moving down the halide series and Na+ exhibits a larger effect than any of the anions. The Ea for water molecules within the second solvation shell of an ion are modest, indicating a short-ranged nature of the ion influence.
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Affiliation(s)
- Ashley K Borkowski
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Zeke A Piskulich
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Ward H Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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218
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Fries MR, Conzelmann NF, Günter L, Matsarskaia O, Skoda MWA, Jacobs RMJ, Zhang F, Schreiber F. Bulk Phase Behavior vs Interface Adsorption: Specific Multivalent Cation and Anion Effects on BSA Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:139-150. [PMID: 33393312 DOI: 10.1021/acs.langmuir.0c02618] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Proteins are ubiquitous and play a critical role in many areas from living organisms to protein microchips. In humans, serum albumin has a prominent role in the foreign body response since it is the first protein which will interact with, e.g., an implant or stent. In this study, we focused on the influence of salts (i.e., different cations (Y3+, La3+) and anions (Cl-, I-) on bovine serum albumin (BSA) in terms of its bulk behavior as well as the role of charges for protein adsorption at the solid-liquid interface in order to understand and control the underlying molecular mechanisms and interactions. This is part of our group's effort to gain a deeper understanding of protein-protein and protein-surface interactions in the presence of multivalent ions. In the bulk, we established two new phase diagrams and found not only multivalent cation-triggered phase transitions, but also a dependence of the protein behavior on the type of anion. The attractive interactions between proteins were observed to increase from Cl- < NO3- < I-, resulting in iodide preventing re-entrant condensation and promoting liquid-liquid phase separation in bulk. Using ellipsometry and a quartz-crystal microbalance with dissipation (QCM-D), we obtained insight into the growth of the protein adsorption layer. Importantly, we found that phase transitions at the substrate can be triggered by certain interface properties, whether they exist in the bulk solution or not. Through the use of a hydrophilic, negatively charged surface (native silica), the direct binding of anions to the interface was prevented. Interestingly, this led to re-entrant adsorption even in the absence of re-entrant condensation in bulk. However, the overall amount of adsorbed protein was enhanced through stronger attractive protein-protein interactions in the presence of iodide salts. These findings illustrate how carefully chosen surface properties and salts can directly steer the binding of anions and cations, which guide protein behavior, thus paving the way for specific/triggered protein-protein, protein-salt, and protein-surface interactions.
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Affiliation(s)
- Madeleine R Fries
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Nina F Conzelmann
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Luzie Günter
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Olga Matsarskaia
- Institut Max von Laue - Paul Langevin (ILL), CS20156, F-38042 Grenoble, France
| | - Maximilian W A Skoda
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, United Kingdom
| | - Robert M J Jacobs
- Department for Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Fajun Zhang
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen, 72076 Tübingen, Germany
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219
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Human-derived NLS enhance the gene transfer efficiency of chitosan. Biosci Rep 2021; 41:227253. [PMID: 33305307 PMCID: PMC7789810 DOI: 10.1042/bsr20201026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 11/25/2020] [Accepted: 12/07/2020] [Indexed: 11/29/2022] Open
Abstract
Nuclear import is considered as one of the major limitations for non-viral gene delivery systems and the incorporation of nuclear localization signals (NLS) that mediate nuclear intake can be used as a strategy to enhance internalization of exogenous DNA. In this work, human-derived endogenous NLS peptides based on insulin growth factor binding proteins (IGFBP), namely IGFBP-3 and IGFBP-5, were tested for their ability to improve nuclear translocation of genetic material by non-viral vectors. Several strategies were tested to determine their effect on chitosan mediated transfection efficiency: co-administration with polyplexes, co-complexation at the time of polyplex formation, and covalent ligation to chitosan. Our results show that co-complexation and covalent ligation of the NLS peptide derived from IGFBP-3 to chitosan polyplexes yields a 2-fold increase in transfection efficiency, which was not observed for NLS peptide derived from IGFBP-5. These results indicate that the integration of IGFBP-NLS-3 peptides into polyplexes has potential as a strategy to enhance the efficiency of non-viral vectors.
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220
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Batys P, Fedorov D, Mohammadi P, Lemetti L, Linder MB, Sammalkorpi M. Self-Assembly of Silk-like Protein into Nanoscale Bicontinuous Networks under Phase-Separation Conditions. Biomacromolecules 2021; 22:690-700. [PMID: 33406825 DOI: 10.1021/acs.biomac.0c01506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Liquid-liquid phase separation of biomacromolecules is crucial in various inter- and extracellular biological functions. This includes formation of condensates to control, e.g., biochemical reactions and structural assembly. The same phenomenon is also found to be critically important in protein-based high-performance biological materials. Here, we use a well-characterized model triblock protein system to demonstrate the molecular level formation mechanism and structure of its condensate. Large-scale molecular modeling supported by analytical ultracentrifuge characterization combined with our earlier high magnification precision cryo-SEM microscopy imaging leads to deducing that the condensate has a bicontinuous network structure. The bicontinuous network rises from the proteins having a combination of sites with stronger mutual attraction and multiple weakly attractive regions connected by flexible, multiconfigurational linker regions. These attractive sites and regions behave as stickers of varying adhesion strength. For the examined model triblock protein construct, the β-sheet-rich end units are the stronger stickers, while additional weaker stickers, contributing to the condensation affinity, rise from spring-like connections in the flexible middle region of the protein. The combination of stronger and weaker sticker-like connections and the flexible regions between the stickers result in a versatile, liquid-like, self-healing structure. This structure also explains the high flexibility, easy deformability, and diffusion of the proteins, decreasing only 10-100 times in the bicontinuous network formed in the condensate phase in comparison to dilute protein solution. The here demonstrated structure and condensation mechanism of a model triblock protein construct via a combination of the stronger binding regions and the weaker, flexible sacrificial-bond-like network as well as its generalizability via polymer sticker models provide means to not only understand intracellular organization, regulation, and cellular function but also to identify direct control factors for and to enable engineering improved protein and polymer constructs to enhance control of advanced fiber materials, smart liquid biointerfaces, or self-healing matrices for pharmaceutics or bioengineering materials.
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Affiliation(s)
- Piotr Batys
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, PL-30239 Krakow, Poland.,Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Dmitrii Fedorov
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Pezhman Mohammadi
- VTT Technical Research Centre of Finland Ltd., FI-02044 Espoo, Finland
| | - Laura Lemetti
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Markus B Linder
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Maria Sammalkorpi
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland.,Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
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221
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The influence of ion identity and ionic strength on membrane biofouling of a binary protein solution. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2020.117769] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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222
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Kotov V, Mlynek G, Vesper O, Pletzer M, Wald J, Teixeira‐Duarte CM, Celia H, Garcia‐Alai M, Nussberger S, Buchanan SK, Morais‐Cabral JH, Loew C, Djinovic‐Carugo K, Marlovits TC. In-depth interrogation of protein thermal unfolding data with MoltenProt. Protein Sci 2021; 30:201-217. [PMID: 33140490 PMCID: PMC7737771 DOI: 10.1002/pro.3986] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 01/06/2023]
Abstract
Protein stability is a key factor in successful structural and biochemical research. However, the approaches for systematic comparison of protein stability are limited by sample consumption or compatibility with sample buffer components. Here we describe how miniaturized measurement of intrinsic tryptophan fluorescence (NanoDSF assay) in combination with a simplified description of protein unfolding can be used to interrogate the stability of a protein sample. We demonstrate that improved protein stability measures, such as apparent Gibbs free energy of unfolding, rather than melting temperature Tm , should be used to rank the results of thermostability screens. The assay is compatible with protein samples of any composition, including protein complexes and membrane proteins. Our data analysis software, MoltenProt, provides an easy and robust way to perform characterization of multiple samples. Potential applications of MoltenProt and NanoDSF include buffer and construct optimization for X-ray crystallography and cryo-electron microscopy, screening for small-molecule binding partners and comparison of effects of point mutations.
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Affiliation(s)
- Vadim Kotov
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
| | - Georg Mlynek
- Department of Structural and Computational Biology, Max Perutz Labs ViennaUniversity of ViennaViennaAustria
| | - Oliver Vesper
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
| | - Marina Pletzer
- Department of Structural and Computational Biology, Max Perutz Labs ViennaUniversity of ViennaViennaAustria
| | - Jiri Wald
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
| | - Celso M. Teixeira‐Duarte
- Instituto de Investigação e Inovação em Saúde (i3S) and Instituto de Biologia Molecular e Celular (IBMC)Universidade do PortoPortoPortugal
| | - Herve Celia
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Maria Garcia‐Alai
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- European Molecular Biology Laboratory (EMBL)Hamburg UnitHamburgGermany
| | - Stephan Nussberger
- Department of Biophysics, Institute of Biomaterials and Biomolecular SystemsUniversity of StuttgartStuttgartGermany
| | - Susan K. Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - João H. Morais‐Cabral
- Instituto de Investigação e Inovação em Saúde (i3S) and Instituto de Biologia Molecular e Celular (IBMC)Universidade do PortoPortoPortugal
| | - Christian Loew
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- European Molecular Biology Laboratory (EMBL)Hamburg UnitHamburgGermany
| | - Kristina Djinovic‐Carugo
- Department of Structural and Computational Biology, Max Perutz Labs ViennaUniversity of ViennaViennaAustria
- Department of Biochemistry, Faculty of Chemistry and Chemical TechnologyUniversity of LjubljanaLjubljanaSlovenia
| | - Thomas C. Marlovits
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
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223
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Influence of salts in the Hofmeister series on the physical gelation behavior of gelatin in aqueous solutions. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2020.106150] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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224
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Mehringer J, Hofmann E, Touraud D, Koltzenburg S, Kellermeier M, Kunz W. Salting-in and salting-out effects of short amphiphilic molecules: a balance between specific ion effects and hydrophobicity. Phys Chem Chem Phys 2021; 23:1381-1391. [DOI: 10.1039/d0cp05491g] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Salting-in or salting-out tendencies depend on a balance between headgroup-specific ion effects and the hydrophobicity of the tail.
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Affiliation(s)
- Johannes Mehringer
- Institute of Theoretical and Physical Chemistry
- University of Regensburg
- 93053 Regensburg
- Germany
| | - Evamaria Hofmann
- Institute of Theoretical and Physical Chemistry
- University of Regensburg
- 93053 Regensburg
- Germany
| | - Didier Touraud
- Institute of Theoretical and Physical Chemistry
- University of Regensburg
- 93053 Regensburg
- Germany
| | | | | | - Werner Kunz
- Institute of Theoretical and Physical Chemistry
- University of Regensburg
- 93053 Regensburg
- Germany
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225
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Kolouchová K, Lobaz V, Beneš H, de la Rosa VR, Babuka D, Švec P, Černoch P, Hrubý M, Hoogenboom R, Štěpánek P, Groborz O. Thermoresponsive properties of polyacrylamides in physiological solutions. Polym Chem 2021. [DOI: 10.1039/d1py00843a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We show that the cloud point temperature (TCP) of thermoresponsive polyacrylamides is considerably lower in physiologically relevant solvents (phosphate-buffered saline, serum) than in pure water. This decrease of TCP may be critical for some biomedical applications.
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Affiliation(s)
- Kristýna Kolouchová
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
| | - Volodymyr Lobaz
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
| | - Hynek Beneš
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
| | - Victor R. de la Rosa
- Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281-S4, 9000 Ghent, Belgium
- AVROXA BV, Technologiepark-Zwijnaarde 82, B-9052 Ghent, Belgium
| | - David Babuka
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
- Department of Biophysics, Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, Prague 2, 121 16, Czech Republic
| | - Pavel Švec
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
- Department of Physical and Macromolecular Chemistry, Faculty of Sciences, Charles University, Hlavova 8, Prague 2, 128 00, Czech Republic
| | - Peter Černoch
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
| | - Martin Hrubý
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
| | - Richard Hoogenboom
- Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281-S4, 9000 Ghent, Belgium
| | - Petr Štěpánek
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
| | - Ondřej Groborz
- Institute of Macromolecular Chemistry, Czech Academy of Science, Heyrovsky square 2, 162 06 Prague 6, Czech Republic
- Institute of Biophysics and Informatics, Charles University, First Faculty of Medicine, Salmovská 1, 120 00 Prague 2, Czech Republic
- Department of Organic and Medicinal Chemistry, Charles University, Faculty of Science, Hlavova 8, 128 43 Prague 2, Czech Republic
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226
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Melro E, Antunes FE, da Silva GJ, Cruz I, Ramos PE, Carvalho F, Alves L. Chitosan Films in Food Applications. Tuning Film Properties by Changing Acidic Dissolution Conditions. Polymers (Basel) 2020; 13:polym13010001. [PMID: 33374920 PMCID: PMC7792621 DOI: 10.3390/polym13010001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 11/16/2022] Open
Abstract
Food contamination due to the presence of microorganisms is a serious problem. New food preservation systems are being studied to kill or inhibit spoilage and pathogenic microorganisms that contaminate food and reduce the shelf life of products. Chitosan films with potential application to food preservation have witnessed great developments during the last years. Chitosan is a cationic polysaccharide with the ability to form films and possess antimicrobial properties. It is water-insoluble but can be dissolved in acidic solutions. In the present work, three different acids (acetic, lactic and citric) were used in chitosan dissolution and both, the resultant solutions and formed films were characterized. It was observed that chitosan water-acetic acid systems show the highest antimicrobial activity due to the highest chitosan charge density, compared to the mixtures with lactic and citric acid. This system showed also the higher solution viscosity compared to the other systems. Chitosan-acetic acid films were also the ones presenting better mechanical properties; this can be attributed to the fact that lactic and citric acids remain in the films, changing their properties, which does not happen with acetic acid. Films produced from chitosan dissolved in water/acetic acid system are resistant, while very fragile but elastic films are formed when lactic acid is used. It was demonstrated that a good selection of the type of acid not only facilitates the dissolution of chitosan but also plays a key role in the properties of the formed solutions and films.
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Affiliation(s)
- Elodie Melro
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal; (E.M.); (F.E.A.)
| | - Filipe E. Antunes
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal; (E.M.); (F.E.A.)
| | - Gabriela J. da Silva
- Center for Neurosciences and Cell Biology and Faculty of Pharmacy, Health Sciences Campus, University of Coimbra, 3000-548 Coimbra, Portugal;
| | - Inês Cruz
- Primor Charcutaria—Prima S.A., Avenida Santiago de Gavião, 1142, 4760-003 Vila Nova de Famalicão, Portugal; (I.C.); (P.E.R.); (F.C.)
| | - Philippe E. Ramos
- Primor Charcutaria—Prima S.A., Avenida Santiago de Gavião, 1142, 4760-003 Vila Nova de Famalicão, Portugal; (I.C.); (P.E.R.); (F.C.)
| | - Fátima Carvalho
- Primor Charcutaria—Prima S.A., Avenida Santiago de Gavião, 1142, 4760-003 Vila Nova de Famalicão, Portugal; (I.C.); (P.E.R.); (F.C.)
| | - Luís Alves
- CIEPQPF, Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, Pólo II, 3030-790 Coimbra, Portugal
- Correspondence:
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227
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Acharyya A, Mukherjee D, Gai F. Assessing the Effect of Hofmeister Anions on the Hydrogen-Bonding Strength of Water via Nitrile Stretching Frequency Shift. J Phys Chem B 2020; 124:11783-11792. [PMID: 33346656 DOI: 10.1021/acs.jpcb.0c06299] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The temperature dependence of the peak frequency (νmax) of the C≡N stretching vibrational spectrum of a hydrogen-bonded C≡N species is known to be a qualitative measure of its hydrogen-bonding strength. Herein, we show that within a two-state framework, this dependence can be analyzed in a more quantitative manner to yield the enthalpy and entropy changes (ΔHHB and ΔSHB) for the corresponding hydrogen-bonding interactions. Using this method, we examine the effect of ten common anions on the strength of the hydrogen-bond(s) formed between water and the C≡N group of an unnatural amino acid, p-cyanophenylalanine (PheCN). We find that based on the ΔHHB values, these anions can be arranged in the following order: HPO42- > OAc- > F- > SO42- ≈ Cl- ≈ (H2O) ≈ ClO4- ≈ NO3- > Br- > SCN- ≈ I-, which differs from the corresponding Hofmeister series. Because PheCN has a relatively small size, the finding that anions having very different charge densities (e.g., SO42- and ClO4-) act similarly suggests that this ranking order is likely the result of specific ion effects. Since proteins contain different backbone and side-chain units, our results highlight the need to assess their individual contributions toward the overall Hofmeister effect in order to achieve a microscopic understanding of how ions affect the physical and chemical properties of such macromolecules. In addition, the analytical method described in the present study is applicable for analyzing the spectral evolution of any vibrational spectra composed of two highly overlapping bands.
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Affiliation(s)
- Arusha Acharyya
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Debopreeti Mukherjee
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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228
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Isolation and Self-Association Studies of Beta-Lactoglobulin. Int J Mol Sci 2020; 21:ijms21249711. [PMID: 33352705 PMCID: PMC7766286 DOI: 10.3390/ijms21249711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/31/2022] Open
Abstract
The aim of this study was to investigate isolated β-lactoglobulin (β-LG) from the whey protein isolate (WPI) solution using the column chromatography with SP Sephadex. The physicochemical characterization (self-association, the pH stability in various salt solutions, the identification of oligomeric forms) of the protein obtained have been carried out. The electrophoretically pure β-LG fraction was obtained at pH 4.8. The fraction was characterized by the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS) technique. The use of the HCCA matrix indicated the presence of oligomeric β-LG forms, while the SA and DHB matrices enabled the differentiation of A and B isoforms in the sample. The impact of sodium chloride, potassium chloride, ammonium sulfate, and sodium citrate in dispersion medium on β-LG electrophoretic stability in solution was also studied. Type of the dispersion medium led to the changes in the isoelectric point of protein. Sodium citrate stabilizes protein in comparison to ammonium sulfate. Additionally, the potential of capillary electrophoresis (CE) with UV detection using bare fused capillary to monitor β-LG oligomerization was discussed. Obtained CE data were further compared by the asymmetric flow field flow fractionation coupled with the multi-angle light scattering detector (AF4-MALS). It was shown that the β-LG is a monomer at pH 3.0, dimer at pH 7.0. At pH 5.0 (near the isoelectric point), oligomers with structures from dimeric to octameric are formed. However, the appearance of the oligomers equilibrium is dependent on the concentration of protein. The higher quantity of protein leads to the formation of the octamer. The far UV circular dichroism (CD) spectra carried out at pH 3.0, 5.0, and 7.0 confirmed that β-sheet conformation is dominant at pH 3.0, 5.0, while at pH 7.0, this conformation is approximately in the same quantity as α-helix and random structures.
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229
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Hershewe JM, Wiseman WD, Kath JE, Buck CC, Gupta MK, Dennis PB, Naik RR, Jewett MC. Characterizing and Controlling Nanoscale Self-Assembly of Suckerin-12. ACS Synth Biol 2020; 9:3388-3399. [PMID: 33201684 DOI: 10.1021/acssynbio.0c00442] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structural proteins such as "suckerins" present promising avenues for fabricating functional materials. Suckerins are a family of naturally occurring block copolymer-type proteins that comprise the sucker ring teeth of cephalopods and are known to self-assemble into supramolecular networks of nanoconfined β-sheets. Here, we report the characterization and controllable, nanoscale self-assembly of suckerin-12 (S12). We characterize the impacts of salt, pH, and protein concentration on S12 solubility, secondary structure, and self-assembly. In doing so, we identify conditions for fabricating ∼100 nm nanoassemblies (NAs) with narrow size distributions. Finally, by installing a noncanonical amino acid (ncAA) into S12, we demonstrate the assembly of NAs that are covalently conjugated with a hydrophobic fluorophore and the ability to change self-assembly and β-sheet content by PEGylation. This work presents new insights into the biochemistry of suckerin-12 and demonstrates how ncAAs can be used to expedite and fine-tune the design of protein materials.
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Affiliation(s)
- Jasmine M. Hershewe
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208−3120, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
| | - William D. Wiseman
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208−3120, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
- Master of Biotechnology Program, Technological Institute, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208−3120, United States
| | - James E. Kath
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208−3120, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
| | - Chelsea C. Buck
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
- Chemical and Materials Engineering Department, University of Dayton, 300 College Park Avenue, Dayton, Ohio 45469, United States
| | - Maneesh K. Gupta
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Patrick B. Dennis
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Rajesh R. Naik
- 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Michael C. Jewett
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208−3120, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Technological Institute E136, Evanston, Illinois 60208−3120, United States
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 676 North Saint Clair Street, Suite 1200, Chicago, Illinois 60611−3068, United States
- Simpson Querrey Institute, Northwestern University, 303 East Superior Street, Suite 11-131, Chicago, Illinois 60611−2875, United States
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230
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Baryiames CP, Ma E, Baiz CR. Ions Slow Water Dynamics at Nonionic Surfactant Interfaces. J Phys Chem B 2020; 124:11895-11900. [DOI: 10.1021/acs.jpcb.0c09086] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher P. Baryiames
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Emily Ma
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Carlos R. Baiz
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
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231
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Panuganti V, Roy I. Oligomers, fibrils and aggregates formed by alpha-synuclein: role of solution conditions. J Biomol Struct Dyn 2020; 40:4389-4398. [PMID: 33292065 DOI: 10.1080/07391102.2020.1856721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The classical Hofmeister series orders ions into kosmotropes and chaotropes, based on their interaction with the solvent, water. The role of protein is mostly ignored probably because most of the proteins studied are natively folded and broadly follow this classification pattern. Recent reports suggest that the interaction of ions is different with solvent molecules of proximal layer and bulk. Intrinsically disordered proteins (IDPs) differ from globular proteins in the fraction of polar vis-à-vis hydrophobic amino acids and the absence of distinct secondary and tertiary structures. The kosmotrope, ammonium sulphate, increases the compactness of the polypeptide conformation, with differing effects for globular proteins and IDPs. For globular proteins, lowered flexibility corresponds to a more stable native structure. Using oligomer-specific and aggregation-specific antibodies and comparing with fibrillation results, we show for alpha-synuclein, an IDP, ammonium sulphate-induced compaction results in the formation of the aggregation-prone hydrophobic core, which combines with other similar moieties to form the fibrillar 'seed'. SEC-HPLC and SAXS analysis show the presence of the threshold oligomers. In the presence of the aggregation suppressor, arginine too, an oligomer is formed. This oligomer, however, is 'dead', and does not move further along the aggregation pathway. Thus, alpha-synuclein undergoes compaction in the presence of protein stabilisers, with differing consequences. In case of the chaotropes, KSCN and urea, aggregation of alpha-synuclein is partially inhibited. However, the amounts and types of aggregates formed are different in the two cases. Thus, the classical catalogue of molecules into protein stabilisers and destabilisers requires a relook for IDPs.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Venkataharsha Panuganti
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Punjab, India
| | - Ipsita Roy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Punjab, India
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232
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The Role of Counter-Ions in Peptides-An Overview. Pharmaceuticals (Basel) 2020; 13:ph13120442. [PMID: 33287352 PMCID: PMC7761850 DOI: 10.3390/ph13120442] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 12/16/2022] Open
Abstract
Peptides and proteins constitute a large group of molecules that play multiple functions in living organisms. In conjunction with their important role in biological processes and advances in chemical approaches of synthesis, the interest in peptide-based drugs is still growing. As the side chains of amino acids can be basic, acidic, or neutral, the peptide drugs often occur in the form of salts with different counter-ions. This review focuses on the role of counter-ions in peptides. To date, over 60 peptide-based drugs have been approved by the FDA. Based on their area of application, biological activity, and results of preliminary tests they are characterized by different counter-ions. Moreover, the impact of counter-ions on structure, physicochemical properties, and drug formulation is analyzed. Additionally, the application of salts as mobile phase additives in chromatographic analyses and analytical techniques is highlighted.
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233
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Ota C, Fukuda Y, Tanaka SI, Takano K. Spectroscopic Evidence of the Salt-Induced Conformational Change around the Localized Electric Charges on the Protein Surface of Fibronectin Type III. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:14243-14254. [PMID: 33197316 DOI: 10.1021/acs.langmuir.0c02367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The effect of salt on the electrostatic interaction of a protein is an important issue, because addition of salt affects protein stability and association/aggregation. Although adding salt is a generally recognized strategy to improve protein stability, this improvement does not necessarily occur. The lack of an effect upon the addition of salt was previously confirmed for the tenth fibronectin type III domain from human fibronectin (FN3) by thermal stability analysis. However, the detailed molecular mechanism is unknown. In the present study, by employing the negatively charged carboxyl triad on the surface of FN3 as a case study, the molecular mechanism of the inefficient NaCl effect on protein stability was experimentally addressed using spectroscopic methods. Complementary analysis using Raman spectroscopy and 8-anilino-1-naphthalenesulfonic acid fluorescence revealed the three-phase behavior of the salt-protein interaction between NaCl and FN3 over a wide salt concentration range from 100 mM to 4.0 M, suggesting that the Na+-specific binding to the negatively charged carboxyl triad causes a local conformational change around the binding site with an accompanying structural change in the overall protein, which contributes to the protein's structural destabilization. This spectroscopic evidence clarifies the molecular understanding of the inefficiency of salt to improve protein stability. The findings will inform the optimization of formulation conditions.
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Affiliation(s)
- Chikashi Ota
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Yui Fukuda
- Department of Biomolecular Chemistry, Kyoto Prefectural University, Sakyo-ku, Kyoto 606-8522, Japan
| | - Shun-Ichi Tanaka
- Department of Biomolecular Chemistry, Kyoto Prefectural University, Sakyo-ku, Kyoto 606-8522, Japan
| | - Kazufumi Takano
- Department of Biomolecular Chemistry, Kyoto Prefectural University, Sakyo-ku, Kyoto 606-8522, Japan
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234
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Neal JF, Saha A, Zerkle MM, Zhao W, Rogers MM, Flood AH, Allen HC. Molecular Recognition and Hydration Energy Mismatch Combine To Inform Ion Binding Selectivity at Aqueous Interfaces. J Phys Chem A 2020; 124:10171-10180. [DOI: 10.1021/acs.jpca.0c09568] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jennifer F. Neal
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Ankur Saha
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Mia M. Zerkle
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wei Zhao
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Mickey M. Rogers
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Amar H. Flood
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Heather C. Allen
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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235
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A cosolvent surfactant mechanism affects polymer collapse in miscible good solvents. Commun Chem 2020; 3:165. [PMID: 36703319 PMCID: PMC9814688 DOI: 10.1038/s42004-020-00405-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/14/2020] [Indexed: 01/29/2023] Open
Abstract
The coil-globule transition of aqueous polymers is of profound significance in understanding the structure and function of responsive soft matter. In particular, the remarkable effect of amphiphilic cosolvents (e.g., alcohols) that leads to both swelling and collapse of stimuli-responsive polymers has been hotly debated in the literature, often with contradictory mechanisms proposed. Using molecular dynamics simulations, we herein demonstrate that alcohols reduce the free energy cost of creating a repulsive polymer-solvent interface via a surfactant-like mechanism which surprisingly drives polymer collapse at low alcohol concentrations. This hitherto neglected role of interfacial solvation thermodynamics is common to all coil-globule transitions, and rationalizes the experimentally observed effects of higher alcohols and polymer molecular weight on the coil-to-globule transition of thermoresponsive polymers. Polymer-(co)solvent attractive interactions reinforce or compensate this mechanism and it is this interplay which drives polymer swelling or collapse.
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236
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Bogunia M, Makowski M. Influence of Ionic Strength on Hydrophobic Interactions in Water: Dependence on Solute Size and Shape. J Phys Chem B 2020; 124:10326-10336. [PMID: 33147018 PMCID: PMC7681779 DOI: 10.1021/acs.jpcb.0c06399] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
![]()
Hydrophobicity is a phenomenon of
great importance in biology,
chemistry, and biochemistry. It is defined as the interaction between
nonpolar molecules or groups in water and their low solubility. Hydrophobic
interactions affect many processes in water, for example, complexation,
surfactant aggregation, and coagulation. These interactions play a
pivotal role in the formation and stability of proteins or biological
membranes. In the present study, we assessed the effect of ionic strength,
solute size, and shape on hydrophobic interactions between pairs of
nonpolar particles. Pairs of methane, neopentane, adamantane, fullerene,
ethane, propane, butane, hexane, octane, and decane were simulated
by molecular dynamics in AMBER 16.0 force field. As a solvent, TIP3P
and TIP4PEW water models were used. Potential of mean force (PMF)
plots of these dimers were determined at four values of ionic strength,
0, 0.04, 0.08, and 0.40 mol/dm3, to observe its impact
on hydrophobic interactions. The characteristic shape of PMFs with
three extrema (contact minimum, solvent-separated minimum, and desolvation
maximum) was observed for most of the compounds for hydrophobic interactions.
Ionic strength affected hydrophobic interactions. We observed a tendency
to deepen contact minima with an increase in ionic strength value
in the case of spherical and spheroidal molecules. Additionally, two-dimensional
distribution functions describing water density and average number
of hydrogen bonds between water molecules were calculated in both
water models for adamantane and hexane. It was observed that the density
of water did not significantly change with the increase in ionic strength,
but the average number of hydrogen bonds changed. The latter tendency
strongly depends on the water model used for simulations.
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Affiliation(s)
- Małgorzata Bogunia
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Mariusz Makowski
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
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237
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Yao W, Wang K, Wu A, Reed WF, Gibb BC. Anion binding to ubiquitin and its relevance to the Hofmeister effects. Chem Sci 2020; 12:320-330. [PMID: 34163600 PMCID: PMC8178748 DOI: 10.1039/d0sc04245e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Although the non-covalent interactions between proteins and salts contributing to the Hofmeister effects have been generally mapped, there are many questions regarding the specifics of these interactions. We report here studies involving the small protein ubiquitin and salts of polarizable anions. These studies reveal a complex interplay between the reverse Hofmeister effect at low pH, the salting-in Hofmeister effect at higher pH, and six anion binding sites in ubiquitin at the root of these phenomena. These sites are all located at protuberances of preorganized secondary structure, and although stronger at low pH, are still apparent when ubiquitin possesses no net charge. These results demonstrate the traceability of these Hofmeister phenomena and suggest new strategies for understanding the supramolecular properties of proteins. Studying the supramolecular properties of Ubiquitin reveals six anion binding sites that contribute to the reverse Hofmeister effect at low pH and the salting-in Hofmeister effect at higher pH.![]()
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Affiliation(s)
- Wei Yao
- Department of Chemistry, Tulane University New Orleans LA 70118 USA
| | - Kaiyu Wang
- Department of Chemistry, Tulane University New Orleans LA 70118 USA
| | - Aide Wu
- Department of Physics and Engineering Physics, Tulane University New Orleans LA 70118 USA
| | - Wayne F Reed
- Department of Physics and Engineering Physics, Tulane University New Orleans LA 70118 USA
| | - Bruce C Gibb
- Department of Chemistry, Tulane University New Orleans LA 70118 USA
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238
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Bitter S, Schlötter M, Schilling M, Krumova M, Polarz S, Winter RF. Ferro-self-assembly: magnetic and electrochemical adaptation of a multiresponsive zwitterionic metalloamphiphile showing a shape-hysteresis effect. Chem Sci 2020; 12:270-281. [PMID: 34163595 PMCID: PMC8178951 DOI: 10.1039/d0sc05249c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Metallosurfactants are molecular compounds which combine the unique features of amphiphiles, like their capability of self-organization, with the peculiar properties of metal complexes like magnetism and a rich redox chemistry. Considering the high relevance of surfactants in industry and science, amphiphiles that change their properties on applying an external trigger are highly desirable. A special feature of the surfactant reported here, 1-(Z)-heptenyl-1′-dimethylammonium-methyl-(3-sulfopropyl)ferrocene (6), is that the redox-active ferrocene constituent is in a gemini-position. Oxidation to 6+ induces a drastic change of the surfactant's properties accompanied by the emergence of paramagnetism. The effects of an external magnetic field on vesicles formed by 6+ and the associated dynamics were monitored in situ using a custom-made optical birefringence and dual dynamic light scattering setup. This allowed us to observe the optical anisotropy as well as the anisotropy of the diffusion coefficient and revealed the field-induced formation of oriented string-of-pearls-like aggregates and their delayed disappearance after the field is switched off. The self-organization properties of a stimuli responsive amphiphile can be altered by subjecting the paramagnetic oxidized form to a magnetic field of 0.8 T and monitored in real time by coupling optical birefringence with dynamic light scattering.![]()
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Affiliation(s)
- Stefan Bitter
- Department of Chemistry, University of Konstanz Universitätsstrasse 10 78457 Konstanz Germany
| | - Moritz Schlötter
- Department of Chemistry, University of Konstanz Universitätsstrasse 10 78457 Konstanz Germany
| | - Markus Schilling
- Department of Chemistry, University of Konstanz Universitätsstrasse 10 78457 Konstanz Germany
| | - Marina Krumova
- Department of Chemistry, University of Konstanz Universitätsstrasse 10 78457 Konstanz Germany
| | - Sebastian Polarz
- Department of Chemistry, University of Konstanz Universitätsstrasse 10 78457 Konstanz Germany .,Institute of Inorganic Chemistry, Leibniz-University Hannover Callinstrasse 9 30167 Hannover Germany
| | - Rainer F Winter
- Department of Chemistry, University of Konstanz Universitätsstrasse 10 78457 Konstanz Germany
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239
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Khalesi H, Lu W, Nishinari K, Fang Y. New insights into food hydrogels with reinforced mechanical properties: A review on innovative strategies. Adv Colloid Interface Sci 2020; 285:102278. [PMID: 33010577 DOI: 10.1016/j.cis.2020.102278] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023]
Abstract
Enhancement on the mechanical properties of hydrogels leads to a wider range of their applications in various fields. Therefore, there has been a great interest recently for developing new strategies to reinforce hydrogels. Moreover, food gels must be edible in terms of both raw materials and production. This paper reviews innovative techniques such as particle/fiber-reinforced hydrogel, double network, dual crosslinking, freeze-thaw cycles, physical conditioning and soaking methods to improve the mechanical properties of hydrogels. Additionally, their fundamental mechanisms, advantages and disadvantages have been discussed. Important biopolymers that have been employed for these strategies and also their potentials in food applications have been summarized. The general mechanism of these strategies is based on increasing the degree of crosslinking between interacting polymers in hydrogels. These links can be formed by adding fillers (oil droplets or fibers in filled gels) or cross-linkers (regarding double network and soaking method) and also by condensation or alignment of the biopolymers (freeze-thaw cycle and physical conditioning) in the gel network. The properties of particle/fiber-reinforced hydrogels extremely depend on the filler, gel matrix and the interaction between them. In freeze-thaw cycles and physical conditioning methods, it is possible to form new links in the gel network without adding any cross-linkers or fillers. It is expected that the utilization of gels will get broader and more varied in food industries by using these strategies.
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240
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Takekiyo T, Yamada N, Amo T, Yoshimura Y. Effects of ethylammonium halides on helix formation of proteins. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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241
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Bruce EE, Okur HI, Stegmaier S, Drexler CI, Rogers BA, van der Vegt NFA, Roke S, Cremer PS. Molecular Mechanism for the Interactions of Hofmeister Cations with Macromolecules in Aqueous Solution. J Am Chem Soc 2020; 142:19094-19100. [PMID: 33124825 DOI: 10.1021/jacs.0c07214] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ion identity and concentration influence the solubility of macromolecules. To date, substantial effort has been focused on obtaining a molecular level understanding of specific effects for anions. By contrast, the role of cations has received significantly less attention and the underlying mechanisms by which cations interact with macromolecules remain more elusive. To address this issue, the solubility of poly(N-isopropylacrylamide), a thermoresponsive polymer with an amide moiety on its side chain, was studied in aqueous solutions with a series of nine different cation chloride salts as a function of salt concentration. Phase transition temperature measurements were correlated to molecular dynamics simulations. The results showed that although all cations were on average depleted from the macromolecule/water interface, more strongly hydrated cations were able to locally accumulate around the amide oxygen. These weakly favorable interactions helped to partially offset the salting-out effect. Moreover, the cations approached the interface together with chloride counterions in solvent-shared ion pairs. Because ion pairing was concentration-dependent, the mitigation of the dominant salting-out effect became greater as the salt concentration was increased. Weakly hydrated cations showed less propensity for ion pairing and weaker affinity for the amide oxygen. As such, there was substantially less mitigation of the net salting-out effect for these ions, even at high salt concentrations.
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Affiliation(s)
- Ellen E Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Halil I Okur
- Department of Chemistry, and National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey.,Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sina Stegmaier
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | | | | | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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242
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Hofmeister Ions Modulate the Autocatalytic Amyloidogenesis of an Intrinsically Disordered Functional Amyloid Domain via Unusual Biphasic Kinetics. J Mol Biol 2020; 432:6173-6186. [PMID: 33068637 DOI: 10.1016/j.jmb.2020.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/01/2020] [Accepted: 10/11/2020] [Indexed: 02/06/2023]
Abstract
Hofmeister ions are thought to play fundamentally important roles in protein solubility, folding, stability, and function. Salt ions profoundly influence the course of protein misfolding, aggregation, and amyloid formation associated with devastating human diseases. However, the molecular origin of the salt-effect in protein aggregation remains elusive. Here, we report an unusual biphasic amyloidogenesis of a pH-responsive, intrinsically disordered, oligopeptide repeat domain of a melanosomal protein, Pmel17, that regulates the amyloid-assisted melanin synthesis in mammals via functional amyloid formation. We demonstrate that a symphony of molecular events involving charge-peptide interactions and hydration, in conjunction with secondary phenomena, critically governs the course of this biphasic amyloid assembly. We show that at mildly acidic pH, typical of melanosomes, highly amyloidogenic oligomeric units assemble into metastable, dendritic, fractal networks following the forward Hofmeister series. However, the subsequent condensation of fractal networks via conformational maturation into amyloid fibrils follows an inverse Hofmeister series due to fragmentation events coupled with secondary nucleation processes. Our results indicate that ions exert a strong influence on the aggregation kinetics as well as on the nanoscale morphology and also modulate the autocatalytic amplification processes during amyloid assembly via an intriguing dual Hofmeister effect. This unique interplay of molecular drivers will be of prime importance in delineating the aggregation pathways of a multitude of intrinsically disordered proteins involved in physiology and disease.
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243
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Grant AM, Krecker MC, Gupta MK, Dennis PB, Crosby MG, Tsukruk VV. Marine Structural Protein Stability Induced by Hofmeister Salt Annealing and Enzymatic Cross-Linking. ACS Biomater Sci Eng 2020; 6:5519-5526. [PMID: 33320559 DOI: 10.1021/acsbiomaterials.0c00791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Humboldt squid is one of the fiercest marine predators thanks in part to its sucker ring teeth that are biopolymer blends of a protein isoform family called suckerin with compression strength that rivals silkworm silk. Here, we focus on the popular suckerin-12 isoform to understand what makes the secondary structure of this biopolymer different in water and the potential role of diverse physical and chemical cross-linkings. By choosing a salt post-treatment, in accordance with the Hofmeister series, we achieved film stability with salt annealing that is comparable to chemical cross-links. By correlating the film morphology with the protein secondary structure changes, suckerin-12 films were shown to contract upon treatment with kosmotropic salts and exhibited increased stability in water. These changes are related to the rearrangement of suckerin-12 secondary structure from random coils and helices to β-sheets. Overall, understanding secondary structure changes caused by aqueous and ionic environments can be instructive for the tuning of the suckerin film sclerotization, its conversion to a tough biological material, and to ultimately produce the natural squid sucker ring teeth.
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Affiliation(s)
- Anise M Grant
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30305, United States
| | - Michelle C Krecker
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30305, United States
| | - Maneesh K Gupta
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Patrick B Dennis
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Marquise G Crosby
- Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Vladimir V Tsukruk
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30305, United States
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244
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Li J, Janoušková O, Fernandez-Alvarez R, Mesíková S, Tošner Z, Kereïche S, Uchman M, Matějíček P. Designed Boron-Rich Polymeric Nanoparticles Based on Nano-ion Pairing for Boron Delivery. Chemistry 2020; 26:14283-14289. [PMID: 32492217 DOI: 10.1002/chem.202001699] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Indexed: 12/13/2022]
Abstract
Boron-rich particles with the boron fraction ca.10-20 wt % of controllable shape and size that can be easily prepared via simple ion co-assembly are promising material for tumor treatment by boron neutron capture therapy. Electroneutral, dynamic core-shell polymeric nanoparticles were prepared by co-assembly of cationic PEO-block-PGEA diblock copolymer with sodium closo-dodecaborate, Na2 [B12 H12 ]. This is the first example of polymer nanoparticles based on [B12 H12 ]2- nano-ion pairing. The high [B12 H12 ]2- loading is proven by calorimetry at physiological salt concentration. As a result of rational design, rod-, worm- and sphere-like particles were produced and further tested using human glioblastoma and cervical carcinoma cell lines. Rod-like particles yielded the highest internalization capability in all tested cell lines.
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Affiliation(s)
- Jianwei Li
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43, Prague 2, Czech Republic
| | - Olga Janoušková
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 16206, Prague 6, Czech Republic
| | - Roberto Fernandez-Alvarez
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43, Prague 2, Czech Republic
| | - Soňa Mesíková
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43, Prague 2, Czech Republic
| | - Zdeněk Tošner
- NMR laboratory, Faculty of Science, Charles University in Prague, Hlavova 2030, 128 43, Prague 2, Czech Republic
| | - Sami Kereïche
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43, Prague 2, Czech Republic.,Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Purkynie Ustav, Albertov 4, 12 801, Prague, Czech Republic
| | - Mariusz Uchman
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43, Prague 2, Czech Republic
| | - Pavel Matějíček
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43, Prague 2, Czech Republic
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245
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Lhee S, Lee JK, Kang J, Kato S, Kim S, Zare RN, Nam HG. Spatial localization of charged molecules by salt ions in oil-confined water microdroplets. SCIENCE ADVANCES 2020; 6:6/41/eaba0181. [PMID: 33028513 PMCID: PMC7541078 DOI: 10.1126/sciadv.aba0181] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 08/19/2020] [Indexed: 05/28/2023]
Abstract
Cells contain more than 100 mM salt ions that are typically confined to dimensions of 5 to 10 micrometers by a hydrophobic cellular membrane. We found that in aqueous microdroplets having the same size as cells and that are confined in hydrocarbon oil, negatively charged molecules were distributed rather uniformly over the interior of the microdroplet, whereas positively charged molecules were localized at and near the surface. However, the addition of salt (NaCl) to the microdroplet caused all charged molecules to be localized near the oil-water interface. This salt-induced relocalization required less salt concentration in microdroplets compared to bulk water. Moreover, the localization became more prominent as the size of the microdroplet was reduced. The relocatization also critically depended on the type of oil. Our results imply that salt ions and different hydrophobic interfaces together may govern the local distribution of charged biomolecules in confined intracellular environments.
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Affiliation(s)
- SangMoon Lhee
- Center for Plant Aging Research, Institute for Basic Science, Daegu 42988, Republic of Korea
| | - Jae Kyoo Lee
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Jooyoun Kang
- Center for Plant Aging Research, Institute for Basic Science, Daegu 42988, Republic of Korea
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Shota Kato
- Center for Plant Aging Research, Institute for Basic Science, Daegu 42988, Republic of Korea
| | - Sunhee Kim
- Center for Plant Aging Research, Institute for Basic Science, Daegu 42988, Republic of Korea
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science, Daegu 42988, Republic of Korea.
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
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246
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Gong S, Wang P, Wei Z, Yang B, Xu X, Xu H, Zheng W. Microsolvation of Sodium Thiocyanate in Water: Gas Phase Anion Photoelectron Spectroscopy and Theoretical Calculations. J Phys Chem A 2020; 124:7816-7826. [DOI: 10.1021/acs.jpca.0c07071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shiyan Gong
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyou Wei
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Yang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiling Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongguang Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weijun Zheng
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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247
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Jiang Y, Zhu Y, Zheng Y, Liu Z, Zhong Y, Deng Y, Zhao Y. Effects of salting-in/out-assisted extractions on structural, physicochemical and functional properties of Tenebrio molitor larvae protein isolates. Food Chem 2020; 338:128158. [PMID: 33091981 DOI: 10.1016/j.foodchem.2020.128158] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 09/11/2020] [Accepted: 09/18/2020] [Indexed: 01/15/2023]
Abstract
Tenebrio molitor larvae protein isolates (TPIs) were extracted using the alkaline extraction and acid precipitation methods (AEAP) assisted by NaCl (salting-in) and (NH4)2SO4 (salting-out) procedures. The structural, physicochemical, and functional properties of TPIs were investigated. It was found that the salt-assisted treatments did not affect the total amino acid content but altered specific amino acid compositions. The salting-in-AEAP extraction resulted in non-significant (P > 0.05) differences in zeta potential, hydrophobicity, thermal stability, solubility and foaming capacity compared with the AEAP extraction. Salting-out-AEAP extraction significantly (P < 0.05) increased overall protein solubility, emulsion activity, foaming capacity and stability that were associated with lower hydrophobicity, higher zeta potential, α-helix and disulfide bond contents. The salting-in-AEAP-out extraction generated the greatest protein yield (39.54%), emulsion activity index (55.5 m2/g), foaming capacity (205%) as well as foaming stability (65.59%).
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Affiliation(s)
- Yongli Jiang
- Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yifan Zhu
- Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yuanrong Zheng
- State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co., Ltd., Shanghai 200436, China
| | - Zhenmin Liu
- State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co., Ltd., Shanghai 200436, China
| | - Yu Zhong
- Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
| | - Yun Deng
- Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yanyun Zhao
- Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Department of Food Science and Technology, 100 Wiegand Hall, Oregon State University, Corvallis, OR, USA
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248
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Liang D, Dahal U, Zhang YK, Lochbaum C, Ray D, Hamers RJ, Pedersen JA, Cui Q. Interfacial water and ion distribution determine ζ potential and binding affinity of nanoparticles to biomolecules. NANOSCALE 2020; 12:18106-18123. [PMID: 32852025 DOI: 10.1039/d0nr03792c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The molecular features that dictate interactions between functionalized nanoparticles and biomolecules are not well understood. This is in part because for highly charged nanoparticles in solution, establishing a clear connection between the molecular features of surface ligands and common experimental observables such as ζ potential requires going beyond the classical models based on continuum and mean field models. Motivated by these considerations, molecular dynamics simulations are used to probe the electrostatic properties of functionalized gold nanoparticles and their interaction with a charged peptide in salt solutions. Counterions are observed to screen the bare ligand charge to a significant degree even at the moderate salt concentration of 50 mM. As a result, the apparent charge density and ζ potential are largely insensitive to the bare ligand charge densities, which fall in the range of ligand densities typically measured experimentally for gold nanoparticles. While this screening effect was predicted by classical models such as the Manning condensation theory, the magnitudes of the apparent surface charge from microscopic simulations and mean-field models are significantly different. Moreover, our simulations found that the chemical features of the surface ligand (e.g., primary vs. quaternary amines, heterogeneous ligand lengths) modulate the interfacial ion and water distributions and therefore the interfacial potential. The importance of interfacial water is further highlighted by the observation that introducing a fraction of hydrophobic ligands enhances the strength of electrostatic binding of the charged peptide. Finally, the simulations highlight that the electric double layer is perturbed upon binding interactions. As a result, it is the bare charge density rather than the apparent charge density or ζ potential that better correlates with binding affinity of the nanoparticle to a charged peptide. Overall, our study highlights the importance of molecular features of the nanoparticle/water interface and underscores a set of design rules for the modulation of electrostatic driven interactions at nano/bio interfaces.
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Affiliation(s)
- Dongyue Liang
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
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249
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Chen J, Qian K, Xiao K, Luo J, Li H, Ma T, Kortz U, Tsige M, Liu T. Co-ion Effects in the Self-Assembly of Macroions: From Co-ions to Co-macroions and to the Unique Feature of Self-Recognition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10519-10527. [PMID: 32787054 DOI: 10.1021/acs.langmuir.0c01797] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Macroions, as soluble ions with a size on the nanometer scale, show unique solution behavior different from those of simple ions and large colloidal suspensions. In macroionic solutions, the counterions are known to be important and well-explored. However, the role of co-ions (ions carrying the same type of charge as the macroions) is often ignored. Here, through experimental and simulation studies, we demonstrate the role of co-ions as a function of co-ion size on their interaction with the macroions (using {Mo72Fe30} and {SrPd12} as models) and the related self-assembly into blackberry-type structures in dilute solutions. Several regimes of unique co-ion effects are clearly identified: small ions (halides, oxoacid ions), subnanometer-scaled bulky ions (lacunary Keggin and dodecaborate ions), and those with sizes comparable to the macroions. Small co-ions have no observable effect on the self-assembly of fully hydrophilic {Mo72Fe30}, while due to hydrophobic interaction and intermolecular hydrogen bonds, the small co-ions show influences on the self-assembly of hydrophobic {SrPd12}. Subnanometer ions, a.k.a. "superchaotropic ions", are still too small to assemble into a blackberry by themselves, but they can coassemble with the macroions, showing a strong interaction with the macroionic system. When the co-ion size is comparable to that of the macroions, they assemble independently instead of assembling with the macroions, leading to the previously reported unique self-recognition phenomenon for macroions.
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Affiliation(s)
- Jiahui Chen
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Kun Qian
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Kexing Xiao
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Jiancheng Luo
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Hui Li
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Tian Ma
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kortz
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
| | - Mesfin Tsige
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Tianbo Liu
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
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250
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Valdes-García J, Rosales-Vázquez LD, Bazany-Rodríguez IJ, Dorazco-González A. Recent Advances in Luminescent Recognition and Chemosensing of Iodide in Water. Chem Asian J 2020; 15:2925-2938. [PMID: 32755069 DOI: 10.1002/asia.202000758] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Indexed: 12/12/2022]
Abstract
This Minireview covers the latest developments of chemosensors based on transition-metal receptors and organic fluorophores with specific binding sites for the luminescent detection and recognition of iodide in aqueous media and real samples. In all selected examples within the last decade (made-post 2010), the iodide sensing and recognition is probed by monitoring real-time changes of the fluorescence or phosphorescence properties of the chemosensors. This review highlights effective strategies to iodide sensing from a structural approach where the iodide recognition/sensing process, through supramolecular interactions as coordination bonds, hydrogen bonds, halogen bonds and electrostatic interactions, is transduced into an optical change easily measurable. The selective iodide sensing is an active field of research with global interest due to the importance of iodide in biological, medicinal, industrial, environmental and chemical processes.
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Affiliation(s)
- Josue Valdes-García
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, CDMX., México
| | - Luis D Rosales-Vázquez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, CDMX., México
| | - Iván J Bazany-Rodríguez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, CDMX., México
| | - Alejandro Dorazco-González
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, CDMX., México
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