1
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Ertekin UE, Okur HI. Greasy Cations Bind to Neutral Macromolecules in Aqueous Solution. J Phys Chem Lett 2024:6151-6157. [PMID: 38835205 DOI: 10.1021/acs.jpclett.4c00925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Ions influence the solution properties of macromolecules. Although much is known about anions, cationic effects are considered mostly in terms of weak interactions or exclusion from neutral interfaces. Herein, we have systematically studied the effect of quaternary tetraalkylammonium cations (NH4+, NMe4+, NEt4+, NPr4+, NBu4+) on the phase transition of poly(N-isopropylacrylamide) (PNIPAM) in aqueous solution. Solubility measurements were coupled to 1H NMR and ATR-FTIR spectroscopic measurements. The solubility and NMR measurements revealed a direct binding between the greasiest cations and the isopropyl group of the macromolecule, evidenced from the nonlinear, Langmuir-type chemical shift response only at the isopropyl NMR signals with increasing salt concentrations. The ATR-FTIR measurements focusing on the amide oxygen showed that it is not the main direct-binding site. Additionally, the salting-out effects of the greasier cations correlate with their hydration entropies. These results demonstrate that the most weakly hydrated cations can bind to macromolecules as strongly as the weakly hydrated Hofmeister anions.
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Affiliation(s)
- Umay Eren Ertekin
- Department of Chemistry, Faculty of Science, Bilkent University, 06800 Ankara, Turkey
| | - Halil Ibrahim Okur
- Department of Chemistry, Faculty of Science, Bilkent University, 06800 Ankara, Turkey
- National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
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2
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Zhu L, Pan Y, Hua Z, Liu Y, Zhang X. Ionic Effect on the Microenvironment of Biomolecular Condensates. J Am Chem Soc 2024; 146:14307-14317. [PMID: 38722189 DOI: 10.1021/jacs.4c04036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Biomolecules such as proteins and RNA could organize to form condensates with distinct microenvironments through liquid-liquid phase separation (LLPS). Recent works have demonstrated that the microenvironment of biomolecular condensates plays a crucial role in mediating biological activities, such as the partition of biomolecules, and the subphase organization of the multiphasic condensates. Ions could influence the phase transition point of LLPS, following the Hofmeister series. However, the ion-specific effect on the microenvironment of biomolecular condensates remains unknown. In this study, we utilized fluorescence lifetime imaging microscopy (FLIM), fluorescence recovery after photobleaching (FRAP), and microrheology techniques to investigate the ion effect on the microenvironment of condensates. We found that ions significantly affect the microenvironment of biomolecular condensates: salting-in ions increase micropolarity and reduce the microviscosity of the condensate, while salting-out ions induce opposing effects. Furthermore, we manipulate the miscibility and multilayering behavior of condensates through ion-specific effects. In summary, our work provides the first quantitative survey of the microenvironment of protein condensates in the presence of ions from the Hofmeister series, demonstrating how ions impact micropolarity, microviscosity, and viscoelasticity of condensates. Our results bear implications on how membrane-less organelles would exhibit varying microenvironments in the presence of continuously changing cellular conditions.
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Affiliation(s)
- Longchen Zhu
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, P. R. China
| | - Yifei Pan
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, P. R. China
| | - Ziyi Hua
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, P. R. China
| | - Yu Liu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xin Zhang
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, P. R. China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, P. R. China
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3
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Gunwant V, Gahtori P, Varanasi SR, Pandey R. Protein-Mediated Changes in Membrane Fluidity and Ordering: Insights into the Molecular Mechanism and Implications for Cellular Function. J Phys Chem Lett 2024; 15:4408-4415. [PMID: 38625684 DOI: 10.1021/acs.jpclett.3c03627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Probing protein-membrane interactions is vital for understanding biological functionality for various applications such as drug development, targeted drug delivery, and creation of functional biomaterials for medical and industrial purposes. In this study, we have investigated interaction of Human Serum Albumin (HSA) with two different lipids, dipalmitoylphosphatidylglycerol (dDPPG) and dipalmitoylphosphatidylcholine (dDPPC), using Vibrational Sum Frequency Generation spectroscopy at different membrane fluidity values. In the liquid-expanded (LE) state of the lipid, HSA (at pH 3.5) deeply intercalated lipid chains through a combination of electrostatic and hydrophobic interactions, which resulted in more ordering of the lipid chains. However, in the liquid-condensed (LC) state, protein intercalation is decreased due to tighter lipid packing. Moreover, our findings revealed distinct differences in HSA's interaction with dDPPG and dDPPC lipids. The interaction with dDPPC remained relatively weak compared to dDPPG. These results shed light on the significance of protein mediated changes in lipid characteristics, which hold considerable implications for understanding membrane protein behavior, lipid-mediated cellular processes, and lipid-based biomaterial design.
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Affiliation(s)
- Vineet Gunwant
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Preeti Gahtori
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Srinivasa Rao Varanasi
- Department of Physics, Sultan Qaboos University, P.O. Box 36, Al-Khoud 123, Muscat, Oman
| | - Ravindra Pandey
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
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4
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Gibb CD, Tran TH, Gibb BC. Assessing Weak Anion Binding to Small Peptides. J Phys Chem B 2024; 128:3605-3613. [PMID: 38592238 PMCID: PMC11033870 DOI: 10.1021/acs.jpcb.4c00657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/11/2024] [Accepted: 03/22/2024] [Indexed: 04/10/2024]
Abstract
Since Hofmeister's seminal studies in the late 19th century, it has been known that salts and buffers can drastically affect the properties of peptides and proteins. These Hofmeister effects can be conceived of in terms of three distinct phenomena/mechanisms: water-salt interactions that indirectly induce the salting-out of a protein by water sequestration by the salt, and direct salt-protein interactions that can either salt-in or salt-out the protein. Unfortunately, direct salt-protein interactions responsible for Hofmeister effects are weak and difficult to quantify. As such, they are frequently construed of as being nonspecific. Nevertheless, there has been considerable effort to better specify these interactions. Here, we use pentapeptides to demonstrate the utility of the H-dimension of nuclear magnetic resonance (NMR) spectroscopy to assess anion binding using N-H signal shifts. We qualify binding using these, demonstrating the upfield shifts induced by anion association and revealing how they are much larger than the corresponding downfield shifts induced by magnetic susceptibility and other ionic strength change effects. We also qualify binding in terms of how the pattern of signal shifts changes with point mutations. In general, we find that the observed upfield shifts are small compared with those induced by anion binding to amide-based hosts, and MD simulations suggest that this is so. Thus, charge-diffuse anions associate mostly with the nonpolar regions of the peptide rather than directly interacting with the amide N-H groups. These findings reveal the utility of 1H NMR spectroscopy for qualifying affinity to peptides─even when affinity constants are very low─and serve as a benchmark for using NMR spectroscopy to study anion binding to more complex systems.
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Affiliation(s)
- Corinne
L. D. Gibb
- Department of Chemistry, Tulane University School of Science and Engineering, New Orleans, Louisiana 70118, United States
| | - Thien H. Tran
- Department of Chemistry, Tulane University School of Science and Engineering, New Orleans, Louisiana 70118, United States
| | - Bruce C. Gibb
- Department of Chemistry, Tulane University School of Science and Engineering, New Orleans, Louisiana 70118, United States
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5
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Maia RN, Mitra S, Baiz CR. Extracting accurate infrared lineshapes from weak vibrational probes at low concentrations. MethodsX 2023; 11:102309. [PMID: 37577166 PMCID: PMC10416016 DOI: 10.1016/j.mex.2023.102309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/31/2023] [Indexed: 08/15/2023] Open
Abstract
Fourier-transform infrared (FTIR) spectroscopy using vibrational probes is an ideal tool to detect changes in structure and local environments within biological molecules. However, challenges arise when dealing with weak infrared probes, such as thiocyanates, due to their inherent low signal strengths and overlap with solvent bands. In this protocol we demonstrate:•A streamlined approach for the precise extraction of weak infrared absorption lineshapes from a strong solvent background.•A protocol combining a spectral filter, background modeling, and subtraction.•Our methodology successfully extracts the CN stretching mode peak from methyl thiocyanate at remarkably low concentrations (0.25 mM) in water, previously a challenge for FTIR spectroscopy.This approach offers valuable insights and tools for more accurate FTIR measurements using weak vibrational probes. This enhanced precision can potentially enable new approaches to enhance our understanding of protein structure and dynamics in solution.
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Affiliation(s)
- Raiza N.A. Maia
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712-1224, USA
| | - Sunayana Mitra
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712-1224, USA
| | - Carlos R. Baiz
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712-1224, USA
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6
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Zhao Y, Bharadwaj S, Myers RL, Okur HI, Bui PT, Cao M, Welsh LK, Yang T, Cremer PS, van der Vegt NFA. Solvation Behavior of Elastin-like Polypeptides in Divalent Metal Salt Solutions. J Phys Chem Lett 2023; 14:10113-10118. [PMID: 37921693 DOI: 10.1021/acs.jpclett.3c02476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
The effects of CaCl2 and MgCl2 on the cloud point temperature of two different elastin-like polypeptides (ELPs) were studied using a combination of cloud point measurements, molecular dynamics simulations, and infrared spectroscopy. Changes in the cloud point for the ELPs in aqueous divalent metal cation solutions were primarily governed by two competing interactions: the cation-amide oxygen electrostatic interaction and the hydration of the cation. In particular, Ca2+ cations can more readily shed their hydration shells and directly contact two amide oxygens by the formation of ion bridges. By contrast, Mg2+ cations were more strongly hydrated and preferred to partition toward the amide oxygens along with their hydration shells. In fact, although hydrophilic ELP V5A2G3 was salted-out at low concentrations of MgCl2, it was salted-in at higher salt concentrations. By contrast, CaCl2 salted the ELP sharply out of solution at higher salt concentrations because of the bridging effect.
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Affiliation(s)
- Yani Zhao
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Swaminath Bharadwaj
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
- Department of Chemical Engineering, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Ryan L Myers
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Halil I Okur
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Pho T Bui
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Mengrui Cao
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Lauren K Welsh
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Tinglu Yang
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
| | - Paul S Cremer
- Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16802, United States
| | - Nico F A van der Vegt
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
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7
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Han Q, Su Y, Smith KM, Binns J, Drummond CJ, Darmanin C, Greaves TL. Probing ion-binding at a protein interface: Modulation of protein properties by ionic liquids. J Colloid Interface Sci 2023; 650:1393-1405. [PMID: 37480654 DOI: 10.1016/j.jcis.2023.07.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 07/24/2023]
Abstract
Ions are important to modulate protein properties, including solubility and stability, through specific ion effects. Ionic liquids (ILs) are designer salts with versatile ion combinations with great potential to control protein properties. Although protein-ion binding of common metals is well-known, the IL effect on proteins is not well understood. Here, we employ the model protein lysozyme in dilute and concentrated IL solutions to determine the specific ion binding effect on protein phase behaviour, activity, size and conformational change, aggregation and intermolecular interactions. A combination of spectroscopic techniques, activity assays, small-angle X-ray scattering, and crystallography highlights that ILs, particularly their anions, bind to specific sites in the protein hydration layer via polar contacts on charged, polar and aromatic residues. The specific ion binding can induce more flexible loop regions in lysozyme, while the ion binding in the bulk phase can be more dynamic in solution. Overall, the protein behaviour in ILs depends on the net effect of nonspecific interactions and specific ion binding. Compared to formate, the nitrate anion induced high protein solubility, low activity, elongated shape and aggregation, which is largely owing to its higher propensity for ion binding. These findings provide new insights into protein-IL binding interactions and using ILs to modulate protein properties.
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Affiliation(s)
- Qi Han
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Yuyu Su
- School of Engineering, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Kate M Smith
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC 3168, Australia; Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, Villigen-PSI, 5232 Villigen, Switzerland
| | - Jack Binns
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
| | - Connie Darmanin
- La Trobe Institute for Molecular Science, Department of Mathematical and Physical Sciences, School of Computing Engineering and Mathematical Science, La Trobe University, Bundoora, VIC 3086, Australia.
| | - Tamar L Greaves
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia.
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8
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Scott HL, Bolmatov D, Premadasa UI, Doughty B, Carrillo JMY, Sacci RL, Lavrentovich M, Katsaras J, Collier CP. Cations Control Lipid Bilayer Memcapacitance Associated with Long-Term Potentiation. ACS APPLIED MATERIALS & INTERFACES 2023; 15:44533-44540. [PMID: 37696028 DOI: 10.1021/acsami.3c09056] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Phospholipid bilayers can be described as capacitors whose capacitance per unit area (specific capacitance, Cm) is determined by their thickness and dielectric constant─independent of applied voltage. It is also widely assumed that the Cm of membranes can be treated as a "biological constant". Recently, using droplet interface bilayers (DIBs), it was shown that zwitterionic phosphatidylcholine (PC) lipid bilayers can act as voltage-dependent, nonlinear memory capacitors, or memcapacitors. When exposed to an electrical "training" stimulation protocol, capacitive energy storage in lipid membranes was enhanced in the form of long-term potentiation (LTP), which enables biological learning and long-term memory. LTP was the result of membrane restructuring and the progressive asymmetric distribution of ions across the lipid bilayer during training, which is analogous, for example, to exponential capacitive energy harvesting from self-powered nanogenerators. Here, we describe how LTP could be produced from a membrane that is continuously pumped into a nonequilibrium steady state, altering its dielectric properties. During this time, the membrane undergoes static and dynamic changes that are fed back to the system's potential energy, ultimately resulting in a membrane whose modified molecular structure supports long-term memory storage and LTP. We also show that LTP is very sensitive to different salts (KCl, NaCl, LiCl, and TmCl3), with LiCl and TmCl3 having the most profound effect in depressing LTP, relative to KCl. This effect is related to how the different cations interact with the bilayer zwitterionic PC lipid headgroups primarily through electric-field-induced changes to the statistically averaged orientations of water dipoles at the bilayer headgroup interface.
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Affiliation(s)
- Haden L Scott
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dima Bolmatov
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Uvinduni I Premadasa
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jan-Michael Y Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Robert L Sacci
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Maxim Lavrentovich
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - John Katsaras
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Charles P Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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9
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Rembert KB, Zhang J, Lee YJ. Effects of Salts and Surface Charge on the Biophysical Stability of a Low pI Monoclonal Antibody. J Pharm Sci 2023; 112:947-953. [PMID: 36395898 DOI: 10.1016/j.xphs.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022]
Abstract
The impact of five representative Hofmeister salts (NaCl, KCl, MgCl2, Na2SO4, and NaSCN) on the thermal stability and aggregation kinetics of a slightly acidic monoclonal antibody (mAb) were investigated under different pH conditions. The thermal stability of the mAb was assessed by measuring the lowest unfolding transition temperature, Tm, with differential scanning fluorimetry. MgCl2 and NaSCN significantly decreased Tm at all three charged states of the mAb, but to the greatest extent when the mAb surface charge was net positive. Non-native aggregation kinetics was monitored by measuring Rayleigh light scattering. When the mAb surface charge was net positive or net neutral, the nucleation rate increased non-monotonically with MgCl2 and NaSCN but decreased monotonically with NaCl, KCl, and Na2SO4. By contrast, when the mAb surface was negatively charged, there were only minor changes in the nucleation rate with all salts tested. Furthermore, there was less structural perturbation and slower aggregation rates when the mAb was net negatively charged than when it was net neutrally or positively charged. The observed salt effects on thermal unfolding are consistent with ion-specific mechanisms dominated by short-range amide backbone binding. On the other hand, the salt effects on nucleation rates appear to be influenced by both amide backbone binding and long-range electrostatic binding of ions to charged amino acid side chains.
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Affiliation(s)
- Kelvin B Rembert
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Jifeng Zhang
- Department of Drug Delivery and Device Development, Medimmune-AstraZeneca, Gaithersburg, MD 20878, United States.
| | - Young Jong Lee
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States.
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10
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Maitra A, Das P, Thompson BC, Dawlaty JM. Distinguishing between the Electrostatic Effects and Explicit Ion Interactions in a Stark Probe. J Phys Chem B 2023; 127:2511-2520. [PMID: 36917012 DOI: 10.1021/acs.jpcb.2c08030] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
Vibrational Stark probes are incisive tools for measuring local electric fields in a wide range of chemical environments. The interpretation of the frequency shift often gets complicated due to the specific interactions of the probe, such as hydrogen bonding and Lewis bonding. Therefore, it is important to distinguish between the pure electrostatic response and the response due to such specific interactions. Here we report a molecular system that is sensitive to both the Stark effect from a single ion and the explicit Lewis bonding of ions with the probe. The molecule consists of a crown ether with an appended benzonitrile. The crown captures cations of various charges, and the electric field from the ions is sensed by the benzonitrile probe. Additionally, the lone pair of the benzonitrile can engage in Lewis interactions with some of the ions by donating partial charge density to the ions. Our system exhibits both of these effects and therefore is a suitable test bed for distinguishing between the pure electrostatic and the Lewis interactions. Our computational results show that the electrostatic influence of the ion is operative at large distances, while the Lewis interaction becomes important only within distances that permit orbital overlap. Our results may be useful for using the nitrile probe for measuring electrostatic and coordination effects in complex ionic environments such as the electrode-electrolyte interfaces.
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Affiliation(s)
- Anwesha Maitra
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Pratyusha Das
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Barry C Thompson
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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11
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Xue B, Lai Y, Liu Y, Li M, Li X, Yin P. The Counterion-Mediated Controllable Coacervation of Nano-Ions with Polyelectrolytes. J Colloid Interface Sci 2023; 641:853-860. [PMID: 36966574 DOI: 10.1016/j.jcis.2023.03.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/22/2023]
Abstract
Nano-ions can complex with polyelectrolytes for coacervates with hierarchical structures; however, the rational design of functional coacervations is still rare due to the poor understanding of their structure-property relationship from their complex interaction. Herein, 1 nm anionic metal oxide clusters, PW12O403-, with well-defined, mono-disperse structures are applied to complex with cationic polyelectrolyte and the system shows tunable coacervation via the alternation of counterions (H+ and Na+) of PW12O403-. Suggested from Fourier transform infrared spectroscopy (FT-IR) and isothermal titration studies, the interaction between PW12O403- and cationic polyelectrolytes can be modulated by the bridging effect of counterions via hydrogen bonding or ion-dipole interaction to carbonyl groups of polyelectrolytes. The condensed structures of the complexed coacervates are explored by small angle X-ray and neutron scattering techniques, respectively. The coacervate with H+ as counterions shows both crystallized and discrete PW12O403- clusters, with a loose polymer-cluster network in comparison to the system of Na+ which shows a dense packing structure with aggregated nano-ions filling the meshes of polyelectrolyte networks. The bridging effect of counterions helps understand the super-chaotropic effect observed in nano-ion system and provides avenues for the design of metal oxide cluster-based functional coacervates.
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12
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Shaiken TE, Grimm SL, Siam M, Williams A, Rezaeian AH, Kraushaar D, Ricco E, Robertson MJ, Coarfa C, Jain A, Malovannaya A, Stossi F, Opekun AR, Price AP, Dubrulle J. Transcriptome, proteome, and protein synthesis within the intracellular cytomatrix. iScience 2023; 26:105965. [PMID: 36824274 PMCID: PMC9941065 DOI: 10.1016/j.isci.2023.105965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 11/07/2022] [Accepted: 01/06/2023] [Indexed: 01/15/2023] Open
Abstract
Despite the knowledge that protein translation and various metabolic reactions that create and sustain cellular life occur in the cytoplasm, the structural organization within the cytoplasm remains unclear. Recent models indicate that cytoplasm contains viscous fluid and elastic solid phases. We separated these viscous fluid and solid elastic compartments, which we call the cytosol and cytomatrix, respectively. The distinctive composition of the cytomatrix included structural proteins, ribosomes, and metabolome enzymes. High-throughput analysis revealed unique biosynthetic pathways within the cytomatrix. Enrichment of biosynthetic pathways in the cytomatrix indicated the presence of immobilized biocatalysis. Enzymatic immobilization and segregation can surmount spatial impediments, and the local pathway segregation may form cytoplasmic organelles. Protein translation was reprogrammed within the cytomatrix under the restriction of protein synthesis by drug treatment. The cytosol and cytomatrix are an elaborately interconnected network that promotes operational flexibility in healthy cells and the survival of malignant cells.
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Affiliation(s)
- Tattym E. Shaiken
- Department of Medicine-Gastroenterology and Hepatology Section, Michael E DeBakey Veteran’s Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA
- PeriNuc Labs, University of Houston Technology Bridge, Houston, TX 77023, USA
| | - Sandra L. Grimm
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mohamad Siam
- Department of Medicine-Gastroenterology and Hepatology Section, Michael E DeBakey Veteran’s Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA
- PeriNuc Labs, University of Houston Technology Bridge, Houston, TX 77023, USA
| | - Amanda Williams
- Department of Medicine-Gastroenterology and Hepatology Section, Michael E DeBakey Veteran’s Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA
- PeriNuc Labs, University of Houston Technology Bridge, Houston, TX 77023, USA
| | - Abdol-Hossein Rezaeian
- PeriNuc Labs, University of Houston Technology Bridge, Houston, TX 77023, USA
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Daniel Kraushaar
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
| | - Emily Ricco
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Cristian Coarfa
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
| | - Antrix Jain
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
| | - Anna Malovannaya
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
| | - Fabio Stossi
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Antone R. Opekun
- Department of Medicine-Gastroenterology and Hepatology Section, Michael E DeBakey Veteran’s Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alyssa P. Price
- Department of Medicine-Gastroenterology and Hepatology Section, Michael E DeBakey Veteran’s Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Julien Dubrulle
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX 77030, USA
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13
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Alia A, Gao F, Mitchell JC, Gasiorowski J, Ciancio M, Kuppast B, Pfeifer C, Carrilho MR. Dentin primer based on a highly functionalized gelatin-methacryloyl hydrogel. Dent Mater 2023; 39:192-203. [PMID: 36641338 DOI: 10.1016/j.dental.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 12/24/2022] [Indexed: 01/13/2023]
Abstract
Gelatin-methacryloyl hydrogels (GelMA) have demonstrated their utility as scaffolds in a variety of tissue engineering applications. OBJECTIVES In this study, a highly functionalized GelMA hydrogel was synthesized and assessed for degree of functionalization. As the proposed GelMA hydrogel was coupled to a visible-light photoinitiator, we hypothesized it might serve as base to formulate a model dentin primer for application in restorative dentistry. METHODS GelMA was mixed with photoinitiator lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), photopolymerized for 0-40 s using a dental light-curing device and tested for extrudability, degree of photo-crosslinking (DPxlink), water sorption/solubility/swelling (WS/SL/SW) and apparent modulus of elasticity (AE). Model dentin primer was prepared by mixing GelMA+LAP with a primer of a commercial three-step etch-and-rinse adhesive. After application of GelMA-based primer to acid-etched dentin, samples were bonded with correspondent adhesive agent, photopolymerized and had their immediate bond strength compared to control samples primed and bonded with the same commercial material. RESULTS Extrudability of hydrogel was confirmed using a microsyringe to write the acronym "CDMI". DPxlink of GelMA+LAP changed significantly as a function of photopolymerization time (20 s < 30 s ≤ 40 s). WS, SL and SW were significantly reduced in hydrogels polymerized for 30 and 40 s. AE of hydrogels varied significantly as a function of photopolymerization time (20 s < 30 s ≤ 40 s; 20 s ‡ 40 s). Bond strength of dentin primed with GelMA-based primer was lower (∼29.3 MPa) but not significantly of that of control (∼34.6 MPa). CONCLUSIONS Optimization of a GelMA-based dentin primers can lead to the development of promising biomimetic adhesives for dentin rehabilitation.
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Affiliation(s)
- Ala Alia
- Midwestern University, College of Graduate Studies, Biomedical Sciences Program, Downers Grove, IL, USA; Midwestern University, College of Dental Medicine-Illinois, Downers Grove, IL, USA
| | - Feng Gao
- Midwestern University, College of Dental Medicine-Illinois, Downers Grove, IL, USA
| | - John C Mitchell
- Midwestern University, College of Dental Medicine-Illinois, Downers Grove, IL, USA; Midwestern University, College of Dental Medicine-Arizona, Glendale, IL, USA
| | - Joshua Gasiorowski
- Midwestern University, College of Graduate Studies, Biomedical Sciences Program, Downers Grove, IL, USA
| | - Mae Ciancio
- Midwestern University, College of Graduate Studies, Biomedical Sciences Program, Downers Grove, IL, USA
| | - Bhimanna Kuppast
- Midwestern University, Chicago College of Pharmacy, Pharmaceutical Sciences, Downers Grove, IL, USA
| | - Carmem Pfeifer
- Oregon Health & Science University, School of Dentistry, Biomaterials and Biomechanics, Portland, OR, USA
| | - Marcela R Carrilho
- Midwestern University, College of Dental Medicine-Illinois, Downers Grove, IL, USA.
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14
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Krevert CS, Gunkel L, Haese C, Hunger J. Ion-specific binding of cations to the carboxylate and of anions to the amide of alanylalanine. Commun Chem 2022; 5:173. [PMID: 36697920 PMCID: PMC9814750 DOI: 10.1038/s42004-022-00789-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
Studies of ion-specific effects on oligopeptides have aided our understanding of Hofmeister effects on proteins, yet the use of different model peptides and different experimental sensitivities have led to conflicting conclusions. To resolve these controversies, we study a small model peptide, L-Alanyl-L-alanine (2Ala), carrying all fundamental chemical protein motifs: C-terminus, amide bond, and N-terminus. We elucidate the effect of GdmCl, LiCl, KCl, KI, and KSCN by combining dielectric relaxation, nuclear magnetic resonance (1H-NMR), and (two-dimensional) infrared spectroscopy. Our dielectric results show that all ions reduce the rotational mobility of 2Ala, yet the magnitude of the reduction is larger for denaturing cations than for anions. The NMR chemical shifts of the amide group are particularly sensitive to denaturing anions, indicative of anion-amide interactions. Infrared experiments reveal that LiCl alters the spectral homogeneity and dynamics of the carboxylate, but not the amide group. Interaction of LiCl with the negatively charged pole of 2Ala, the COO- group, can explain the marked cationic effect on dipolar rotation, while interaction of anions between the poles, at the amide, only weakly perturbs dipolar dynamics. As such, our results provide a unifying view on ions' preferential interaction sites at 2Ala and help rationalize Hofmeister effects on proteins.
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Affiliation(s)
- Carola Sophie Krevert
- grid.419547.a0000 0001 1010 1663Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Lucas Gunkel
- grid.419547.a0000 0001 1010 1663Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Constantin Haese
- grid.419547.a0000 0001 1010 1663Department of Molecular Electronics, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Johannes Hunger
- grid.419547.a0000 0001 1010 1663Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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15
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Lin L, Liu Z, Premadasa UI, Li T, Ma YZ, Sacci RL, Katsaras J, Hong K, Collier CP, Carrillo JMY, Doughty B. The Unexpected Role of Cations in the Self-Assembly of Positively Charged Amphiphiles at Liquid/Liquid Interfaces. J Phys Chem Lett 2022; 13:10889-10896. [PMID: 36394318 DOI: 10.1021/acs.jpclett.2c02921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Conventional wisdom suggests that cations play a minimal role in the assembly of cationic amphiphiles. Here, we show that at liquid/liquid (L/L) interfaces, specific cation effects can modulate the assemblies of hydrophobic tails in an oil phase despite being attached to cationic headgroups in the aqueous phase. We used oligo-dimethylsiloxane (ODMS) methyl imidazolium amphiphiles to identify these specific interactions at hexadecane/aqueous interfaces. Small cations, such as Li+, bind to the O atoms in the ODMS tail and pin it to the interface, thereby imposing a kinked conformation─as evidenced by vibrational sum frequency generation spectroscopy and molecular dynamics simulations. While larger Cs+ ions more readily partition to the interface, they do not form analogous complexes. Our data not only point to ways for controlling amphiphile structure at L/L interfaces but also suggest a means for the separation of Li+, or related applications, in soft-matter electronics.
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Affiliation(s)
- Lu Lin
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Zening Liu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Uvinduni I Premadasa
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Tianyu Li
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Robert L Sacci
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - John Katsaras
- Laboratories and Soft Matter Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Kunlun Hong
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - C Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Jan-Michael Y Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
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16
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Wang X, Yang D, Zhang M, Hu Q, Gao K, Zhou J, Yu ZZ. Super-Hygroscopic Calcium Chloride/Graphene Oxide/Poly(N-isopropylacrylamide) Gels for Spontaneous Harvesting of Atmospheric Water and Solar-Driven Water Release. ACS APPLIED MATERIALS & INTERFACES 2022; 14:33881-33891. [PMID: 35849823 DOI: 10.1021/acsami.2c08591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Although atmospheric water harvesting is a promising approach for extracting clean water in water deficient areas, most atmospheric water collectors require additional energy for releasing the water absorbed. It is still challenging to improve both moisture absorption capacity and desorption efficiency of moisture water collectors. Inspired by clean solar energy and the large humidity difference between day and night, super-hygroscopic calcium chloride (CaCl2)/graphene oxide (GO)/poly(N-isopropylacrylamide) (PNIPAM) gels are designed for spontaneous collection of atmospheric water in a wide range of relative humidity (RH) followed by solar-driven release of the water absorbed. An optimal CaCl2/GO/PNIPAM hygroscopic gel possesses a hierarchical porous structure with directional water transport channels, facilitating water capture and release, thus exhibiting a high moisture absorption capacity of up to 3.6 g g-1 at an RH of 90%. Driven by simulated sunlight, the solar-thermal energy conversion effect of the GO component triggers a unique hydrophilic-hydrophobic conformational transition and shrinkage of the PNIPAM for efficient release of the water absorbed. The integration of the spontaneous harvesting of atmospheric water and the solar-driven water release makes the super-hygroscopic gels promising for efficiently utilizing atmospheric water for special applications where water is desperately necessary but unavailable.
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Affiliation(s)
- Xuejiao Wang
- Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China
- State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Dongzhi Yang
- Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Ming Zhang
- Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Qian Hu
- State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Kejing Gao
- Petrochina Petrochemical Research Institute, Beijing 102206, China
| | - Jingsheng Zhou
- Petrochina Petrochemical Research Institute, Beijing 102206, China
| | - Zhong-Zhen Yu
- State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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17
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Balos V, Kaliannan NK, Elgabarty H, Wolf M, Kühne TD, Sajadi M. Time-resolved terahertz-Raman spectroscopy reveals that cations and anions distinctly modify intermolecular interactions of water. Nat Chem 2022; 14:1031-1037. [PMID: 35773490 PMCID: PMC9417992 DOI: 10.1038/s41557-022-00977-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 05/16/2022] [Indexed: 11/09/2022]
Abstract
The solvation of ions changes the physical, chemical and thermodynamic properties of water, and the microscopic origin of this behaviour is believed to be ion-induced perturbation of water's hydrogen-bonding network. Here we provide microscopic insights into this process by monitoring the dissipation of energy in salt solutions using time-resolved terahertz-Raman spectroscopy. We resonantly drive the low-frequency rotational dynamics of water molecules using intense terahertz pulses and probe the Raman response of their intermolecular translational motions. We find that the intermolecular rotational-to-translational energy transfer is enhanced by highly charged cations and is drastically reduced by highly charged anions, scaling with the ion surface charge density and ion concentration. Our molecular dynamics simulations reveal that the water-water hydrogen-bond strength between the first and second solvation shells of cations increases, while it decreases around anions. The opposite effects of cations and anions on the intermolecular interactions of water resemble the effects of ions on the stabilization and denaturation of proteins.
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Affiliation(s)
- Vasileios Balos
- Fritz Haber Institute of the Max-Planck Society, Berlin, Germany. .,IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, Madrid, Spain.
| | - Naveen Kumar Kaliannan
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany
| | - Hossam Elgabarty
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany.
| | - Martin Wolf
- Fritz Haber Institute of the Max-Planck Society, Berlin, Germany
| | - Thomas D Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany
| | - Mohsen Sajadi
- Fritz Haber Institute of the Max-Planck Society, Berlin, Germany. .,Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany.
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18
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Gregory KP, Elliott GR, Robertson H, Kumar A, Wanless EJ, Webber GB, Craig VSJ, Andersson GG, Page AJ. Understanding specific ion effects and the Hofmeister series. Phys Chem Chem Phys 2022; 24:12682-12718. [PMID: 35543205 DOI: 10.1039/d2cp00847e] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Specific ion effects (SIE), encompassing the Hofmeister Series, have been known for more than 130 years since Hofmeister and Lewith's foundational work. SIEs are ubiquitous and are observed across the medical, biological, chemical and industrial sciences. Nevertheless, no general predictive theory has yet been able to explain ion specificity across these fields; it remains impossible to predict when, how, and to what magnitude, a SIE will be observed. In part, this is due to the complexity of real systems in which ions, counterions, solvents and cosolutes all play varying roles, which give rise to anomalies and reversals in anticipated SIEs. Herein we review the historical explanations for SIE in water and the key ion properties that have been attributed to them. Systems where the Hofmeister series is perturbed or reversed are explored, as is the behaviour of ions at the liquid-vapour interface. We discuss SIEs in mixed electrolytes, nonaqueous solvents, and in highly concentrated electrolyte solutions - exciting frontiers in this field with particular relevance to biological and electrochemical applications. We conclude the perspective by summarising the challenges and opportunities facing this SIE research that highlight potential pathways towards a general predictive theory of SIE.
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Affiliation(s)
- Kasimir P Gregory
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia. .,Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Gareth R Elliott
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Hayden Robertson
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Anand Kumar
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Erica J Wanless
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Grant B Webber
- School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Vincent S J Craig
- Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Gunther G Andersson
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Alister J Page
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
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19
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Sun L, Gong J, Xu B, Wang Y, Ding X, Zhang Y, Liu C, Zhao L, Xu B. Ion-Specific Effects on Vesicle-to-Micelle Transitions of an Amino Acid Surfactant Probed by Chemical Trapping. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6295-6304. [PMID: 35476409 DOI: 10.1021/acs.langmuir.1c03415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ion-specific effects widely exist in biological and chemical systems and cannot be explained by classical theories. The complexity of ion-specific effects in protein systems at the molecular level necessitates the use of mimetic models involving smaller molecules, such as amino acids, oligopeptides, and other organic molecules bearing amide bonds. Therefore, it is of theoretical value to determine the effect of additional salts on the aggregation transitions of acyl amino acid surfactants. Herein, the effects of specific tetraalkylammonium ions (TAA+) on sodium lauroyl glycinate (SLG) aggregation were studied by dynamic light scattering (DLS) and transmission electron microscopy. Although previous studies have shown that the kosmotropic TAA+ ions tend to induce micellar growth or micelle-to-vesicle transitions of some anionic surfactants, TAA+ addition in the present study induced partial vesicle-to-micelle transitions in SLG solutions. The chemical trapping (CT) method was employed to estimate changes in the interfacial molarities of water, amide bonds, and carboxylate groups during such transitions. The vesicle-to-micelle transitions were accompanied by a marked rise in interfacial water molarity and a decline in interfacial amide bonds molarity, suggesting that the hydrated TAA+ entered the interfacial region and disrupted hydrogen bonding, thus preventing the SLG monomers from packing tightly. Molecular dynamic simulation was also performed to demonstrate the salt-induced cleavage of amide-amide bonds between SLG headgroups. Furthermore, both CT and DLS results show that the ability of tetraalkylammonium cations to induce such transitions increased with increasing size and hydrophobicity of the cation, which follows the Hofmeister series. The current study offers critical molecular-level evidence for understanding the specific effects of tetraalkylammonium ions on the aggregation transitions of an acyl amino acid surfactant.
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Affiliation(s)
- Lijie Sun
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
| | - Jiani Gong
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
| | - Bo Xu
- McIntire School of Commerce, University of Virginia, Charlottesville, Virginia 22903, United States
| | - Yuzhao Wang
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
| | - Xiaoxuan Ding
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
| | - Yongliang Zhang
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | - Changyao Liu
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
| | - Li Zhao
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
| | - Baocai Xu
- Department of Daily Chemical Engineering, Beijing Technology and Business University, No. 11 Fucheng Road, Beijing 100048, People's Republic of China
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20
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Asakereh I, Lee K, Francisco OA, Khajehpour M. Hofmeister Effects of Group II Cations as Seen in the Unfolding of Ribonuclease A. Chemphyschem 2022; 23:e202100884. [PMID: 35421259 DOI: 10.1002/cphc.202100884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/14/2022] [Indexed: 11/06/2022]
Abstract
This work studies the effects of alkaline-earth cation addition upon the unfolding free energy of a model protein, pancreatic Ribonuclease A (RNase A) by DSC analysis. RNase A was chosen because it: a) does not specifically bind Mg 2+ , Ca 2+ and Sr 2+ cations and b) maintains its structural integrity throughout a large pH range. We have measured and compared the effects of NaCl, MgCl 2 , CaCl 2 and SrCl 2 addition on the melting point of RNase A. Our results show that even though the addition of group II cations to aqueous solvent reduces the solubility of nonpolar residues (and enhances the hydrophobic effect), their interactions with the amide moieties are strong enough to "salt-them-in" the solvent, thereby causing an overall reduction in protein stability. We demonstrate that amide-cation interactions are a major contributor to the observed "Hofmeister Effects" of group II cations in protein folding. Our analysis suggests that protein folding "Hofmeister Effects" of group II cations, are mostly the aggregate sum of how cation addition simultaneously salts-out hydrophobic moieties through increasing the cavitation free energy, while promoting the salting-in of amide moieties through contact pair formation.
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Affiliation(s)
- Iman Asakereh
- University of Manitoba, Chemistry, Dept of Chemistry, University of Manitob, Winnipeg, R3T2N2, Winnipeg, CANADA
| | - Katherine Lee
- University of Manitoba, Chemistry, Dept of Chemistry, University of Manitob, Winnipeg, R3T2N2, Winnipeg, CANADA
| | - Olga A Francisco
- University of Manitoba, Chemistry, Dept of Chemistry, University of Manitob, Winnipeg, R3T2N2, Winnipeg, CANADA
| | - Mazdak Khajehpour
- University of Manitoba, Chemistry, Dept of Chemistry, University of Manitob, R3T2N2, Winnipeg, CANADA
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21
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Pal VK, Roy S. Cooperative Metal Ion Coordination to the Short Self-Assembling Peptide Promotes Hydrogelation and Cellular Proliferation. Macromol Biosci 2022; 22:e2100462. [PMID: 35257490 DOI: 10.1002/mabi.202100462] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/14/2022] [Indexed: 11/12/2022]
Abstract
Non-covalent interactions among short peptides and proteins led to their molecular self-assembly into supramolecular packaging, which provides the fundamental basis of life. These biomolecular assemblies are highly susceptible to the environmental conditions, including temperature, light, pH, and ionic concentration, thus inspiring the fabrication of a new class of stimuli-responsive biomaterials. Here, we report for the first time the cooperative effect of the divalent metal ions to promote hydrogelation in the short collagen inspired self-assembling peptide for developing advanced biomaterials. Introduction of the biologically relevant metal ions (Ca2+ /Mg2+ ) to the peptide surpasses its limitation to self-assemble into a multi-scale structure at physiological pH. In particular, in presence of metal ions, the negatively charged peptide showed a distinct shift in its equilibrium point of gelation and demonstrated conversion from sol to gel and thus enabling the scope of fabricating an advanced biomaterial for controlling cellular behaviour. Interestingly, tunable mechanical strength and improved cellular response were observed within ion-coordinated peptide hydrogels compared to the peptide gelator. Microscopic analyses, rheological assessment, and biological studies established the importance of utilizing a novel strategy by simply using metal ions to modulate the physical and biological attributes of CIPs to construct next-generation biomaterials. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Vijay Kumar Pal
- Institute of Nano Science and Technology, Sector 81, Knowledge City, Sahibzada Ajit Singh Nagar, Punjab, Pin-140306
| | - Sangita Roy
- Institute of Nano Science and Technology, Sector 81, Knowledge City, Sahibzada Ajit Singh Nagar, Punjab, Pin-140306
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22
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Zhao J, Dong T, Yu P, Wang J. Conformation and Metal Cation Binding of Zwitterionic Alanine Tripeptide in Saline Solutions by Infrared Vibrational Spectroscopy and Molecular Dynamics Simulations. J Phys Chem B 2021; 126:161-173. [PMID: 34968072 DOI: 10.1021/acs.jpcb.1c10034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, linear infrared (IR) spectroscopy and molecular dynamics (MD) simulations were used to examine the interaction of different metal cations (Na+, Ca2+, Mg2+, and Zn2+) with backbone (amide C═O) and C-terminal carboxylate (COO-) groups in zwitterionic alanine tripeptide (Ala3) in aqueous solutions with varying saline concentrations. Circular dichroism spectra and MD results suggest that Ala3 is predominantly in polyproline-II (PPII) conformation, whose amide-I and asymmetric carboxylate stretching IR vibration signatures are also supported by quantum-chemistry calculations. The zwitterionic form of Ala3 separates the two amide-I modes in frequency, which are weakly coupled modes, as revealed by two-dimensional IR measurement, and can be used to probe backbone-cation interactions at different scenarios (near charged or neutral chemical groups respectively). Cation concentration-dependent IR frequency red shifts in the amide-I mode are seen for both amide-I modes, whereas blue shifts are also seen in the amide-I mode far from the NH3+ group. The observed spectral changes are discussed from the perspective of the salting-in and salting-out abilities of the cations. In addition, all the metal cations studied here (except Zn2+) can specifically coordinate to the COO- group in bidentate and pseudo-bridging forms simultaneously. For Zn2+, only the pseudo-bridging form exists. Our results shed light on the macroscopic protein salting-in and salting-out phenomena from the perspective of key chemical bonds in peptides.
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Affiliation(s)
- Juan Zhao
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Tiantian Dong
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Pengyun Yu
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jianping Wang
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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23
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Ribeiro SS, Castro TG, Gomes CM, Marcos JC. Hofmeister effects on protein stability are dependent on the nature of the unfolded state. Phys Chem Chem Phys 2021; 23:25210-25225. [PMID: 34730580 DOI: 10.1039/d1cp02477a] [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
The interpretation of a salt's effect on protein stability traditionally discriminates low concentration regimes (<0.3 M), dominated by electrostatic forces, and high concentration regimes, generally described by ion-specific Hofmeister effects. However, increased theoretical and experimental studies have highlighted observations of the Hofmeister phenomena at concentration ranges as low as 0.001 M. Reasonable quantitative predictions of such observations have been successfully achieved throughout the inclusion of ion dispersion forces in classical electrostatic theories. This molecular description is also on the basis of quantitative estimates obtained resorting to surface/bulk solvent partition models developed for ion-specific Hofmeister effects. However, the latter are limited by the availability of reliable structures representative of the unfolded state. Here, we use myoglobin as a model to explore how ion-dependency on the nature of the unfolded state affects protein stability, combining spectroscopic techniques with molecular dynamic simulations. To this end, the thermal and chemical stability of myoglobin was assessed in the presence of three different salts (NaCl, (NH4)2SO4 and Na2SO4), at physiologically relevant concentrations (0-0.3 M). We observed mild destabilization of the native state induced by each ion, attributed to unfavorable neutralization and hydrogen-bonding with the protein side-chains. Both effects, combined with binding of Na+, Cl- and SO42- to the thermally unfolded state, resulted in an overall destabilization of the protein. Contrastingly, ion binding was hindered in the chemically unfolded conformation, due to occupation of the binding sites by urea molecules. Such mechanistic action led to a lower degree of destabilization, promoting surface tension effects that stabilized myoglobin according to the Hofmeister series. Therefore, we demonstrate that Hofmeister effects on protein stability are modulated by the heterogeneous physico-chemical nature of the unfolded state. Altogether, our findings evidence the need to characterize the structure of the unfolded state when attempting to dissect the molecular mechanisms underlying the effects of salts on protein stability.
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Affiliation(s)
- Sara S Ribeiro
- Centre of Chemistry, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Tarsila G Castro
- Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Cláudio M Gomes
- Biosystems and Integrative Sciences Institute, Faculdade de Ciências and Departamento de Química e Bioquímica, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - João C Marcos
- Centre of Chemistry, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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24
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25
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Drexler CI, Cracchiolo OM, Myers RL, Okur HI, Serrano AL, Corcelli SA, Cremer PS. Local Electric Fields in Aqueous Electrolytes. J Phys Chem B 2021; 125:8484-8493. [PMID: 34313130 DOI: 10.1021/acs.jpcb.1c03257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vibrational Stark shifts were explored in aqueous solutions of organic molecules with carbonyl- and nitrile-containing constituents. In many cases, the vibrational resonances from these moieties shifted toward lower frequency as salt was introduced into solution. This is in contrast to the blue-shift that would be expected based upon Onsager's reaction field theory. Salts containing well-hydrated cations like Mg2+ or Li+ led to the most pronounced Stark shift for the carbonyl group, while poorly hydrated cations like Cs+ had the greatest impact on nitriles. Moreover, salts containing I- gave rise to larger Stark shifts than those containing Cl-. Molecular dynamics simulations indicated that cations and anions both accumulate around the probe in an ion- and probe-dependent manner. An electric field was generated by the ion pair, which pointed from the cation to the anion through the vibrational chromophore. This resulted from solvent-shared binding of the ions to the probes, consistent with their positions in the Hofmeister series. The "anti-Onsager" Stark shifts occur in both vibrational spectroscopy and fluorescence measurements.
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Affiliation(s)
| | - Olivia M Cracchiolo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | | | - Halil I Okur
- Department of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
| | - Arnaldo L Serrano
- 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
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26
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Cao Y, Ren L, Zhang Y, Lu X, Zhang X, Yan J, Li W, Masuda T, Zhang A. Remarkable Effects of Anions on the Chirality of Thermoresponsive Helical Dendronized Poly(phenylacetylene)s. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00917] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuexin Cao
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Liangxuan Ren
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Yangwen Zhang
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Xueting Lu
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Xiacong Zhang
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Jiatao Yan
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Wen Li
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Toshio Masuda
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
| | - Afang Zhang
- International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Materials Building Room 447, Nanchen Street 333, Shanghai 200444, China
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27
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Hebal H, Boucherba N, Binay B, Turunen O. Activity and stability of hyperthermostable cellulases and xylanases in ionic liquids. BIOCATAL BIOTRANSFOR 2021. [DOI: 10.1080/10242422.2021.1882430] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Hakim Hebal
- Laboratoire de Microbiologie Appliquée (LMA), Faculté des Sciences de La Nature et de La Vie (FSNV), Université de Bejaia, Bejaia, Algeria
- Faculty of Exact Sciences and Sciences of Nature and Life, Department of Biology, Mohamed Khider University of Biskra, Biskra, Algeria
| | - Nawel Boucherba
- Laboratoire de Microbiologie Appliquée (LMA), Faculté des Sciences de La Nature et de La Vie (FSNV), Université de Bejaia, Bejaia, Algeria
| | - Baris Binay
- Department of Bioengineering, Gebze Technical University, Kocaeli, Turkey
| | - Ossi Turunen
- School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
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28
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Rana S, Kherb J. Fluorimetric detection of distinct lyotropic anion interactions on nanoscopic surfaces. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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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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30
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Giubertoni G, Pérez de Alba Ortíz A, Bano F, Zhang X, Linhardt RJ, Green DE, DeAngelis PL, Koenderink GH, Richter RP, Ensing B, Bakker HJ. Strong Reduction of the Chain Rigidity of Hyaluronan by Selective Binding of Ca 2+ Ions. Macromolecules 2021; 54:1137-1146. [PMID: 33583956 PMCID: PMC7879427 DOI: 10.1021/acs.macromol.0c02242] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/08/2020] [Indexed: 01/09/2023]
Abstract
![]()
The
biological functions of natural polyelectrolytes are strongly
influenced by the presence of ions, which bind to the polymer chains
and thereby modify their properties. Although the biological impact
of such modifications is well recognized, a detailed molecular picture
of the binding process and of the mechanisms that drive the subsequent
structural changes in the polymer is lacking. Here, we study the molecular
mechanism of the condensation of calcium, a divalent cation, on hyaluronan,
a ubiquitous polymer in human tissues. By combining two-dimensional
infrared spectroscopy experiments with molecular dynamics simulations,
we find that calcium specifically binds to hyaluronan at millimolar
concentrations. Because of its large size and charge, the calcium
cation can bind simultaneously to the negatively charged carboxylate
group and the amide group of adjacent saccharide units. Molecular
dynamics simulations and single-chain force spectroscopy measurements
provide evidence that the binding of the calcium ions weakens the
intramolecular hydrogen-bond network of hyaluronan, increasing the
flexibility of the polymer chain. We also observe that the binding
of calcium to hyaluronan saturates at a maximum binding fraction of
∼10–15 mol %. This saturation indicates that the binding
of Ca2+ strongly reduces the probability of subsequent
binding of Ca2+ at neighboring binding sites, possibly
as a result of enhanced conformational fluctuations and/or electrostatic
repulsion effects. Our findings provide a detailed molecular picture
of ion condensation and reveal the severe effect of a few, selective
and localized electrostatic interactions on the rigidity of a polyelectrolyte
chain.
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Affiliation(s)
| | - Alberto Pérez de Alba Ortíz
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Fouzia Bano
- School of Biomedical Sciences, Faculty of Biological Sciences, School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, Astbury Centre of Structural Molecular Biology, and Bragg Centre for Materials Research, University of Leeds, LS2 9JT Leeds, U.K
| | - Xing Zhang
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, 12180 New York, United States
| | - Robert J Linhardt
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, 12180 New York, United States
| | - Dixy E Green
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., Oklahoma, 73104 Oklahoma, United States
| | - Paul L DeAngelis
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., Oklahoma, 73104 Oklahoma, United States
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Ralf P Richter
- School of Biomedical Sciences, Faculty of Biological Sciences, School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, Astbury Centre of Structural Molecular Biology, and Bragg Centre for Materials Research, University of Leeds, LS2 9JT Leeds, U.K
| | - Bernd Ensing
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Huib J Bakker
- AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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31
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Kashid SM, Singh RK, Kwon H, Seol JG, Kim YS, Mukherjee A, Bagchi S. Reply to "Comment on 'Arresting an Unusual Amide Tautomer Using Divalent Cations'". J Phys Chem B 2021; 125:479-483. [PMID: 33301319 DOI: 10.1021/acs.jpcb.0c06005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Somnath M Kashid
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Reman K Singh
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| | - Hyejin Kwon
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Korea
| | - Jin Gyu Seol
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Korea
| | - Yung Sam Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Korea
| | - Arnab Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| | - Sayan Bagchi
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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32
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Drexler CI, Koehler SJ, Myers RL, Lape BA, Elacqua E, Cremer PS. Comment on “Arresting an Unusual Amide Tautomer Using Divalent Cations”. J Phys Chem B 2020; 125:477-478. [DOI: 10.1021/acs.jpcb.0c04272] [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]
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33
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Zhao J, Wang J. Specific and non-specific interactions between metal cations and zwitterionic alanine tripeptide in saline solutions reported by the symmetric carboxylate stretching and amide-II vibrations. Phys Chem Chem Phys 2020; 22:25042-25053. [PMID: 33112337 DOI: 10.1039/d0cp04247a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The "specific" interaction between metal cations (Na+, Ca2+, Mg2+, and Zn2+) and the charged COO- group, and the "non-specific" interaction between these cations and the peptide backbone of a zwitterionic trialanine (Ala3) in aqueous solutions were examined in detail, using linear infrared (IR) absorptions of the COO- symmetric stretching and the amide-II (mainly the C-N stretching) modes as IR probes. Different IR spectral changes in peak positions and intensities of the two IR probes clearly demonstrate their sensitivities to nearby cation distributions in distance and population. Quantum chemistry calculations and molecular dynamics simulations were used to describe the cation-peptide interaction picture. These combined results suggest that Na+ and Ca2+ tend to bind to the COO- group in the bidentate form, while Mg2+ and Zn2+ tend to bind to the COO- group in the pseudo-bridging form. The results also show that while all three divalent cations indirectly interact with the peptide backbone with large population, Ca2+ and Mg2+ can be sometimes distributed very close to the backbone. Such a non-specific cation interaction can be moderately sensed by the C-N stretching of the amide-II mode when cations approach the polar amide C[double bond, length as m-dash]O group, and is also influenced by the NH3+ charge group located at the N-terminus. The results suggest that the experimentally observed complication of the Hofmeister cation series shall be understood as a combined specific and non-specific cation-peptide interactions.
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Affiliation(s)
- Juan Zhao
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
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34
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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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35
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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: 42] [Impact Index Per Article: 10.5] [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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36
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Chemical modifications and their effects on gluten protein: An extensive review. Food Chem 2020; 343:128398. [PMID: 33268180 DOI: 10.1016/j.foodchem.2020.128398] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/28/2020] [Accepted: 10/11/2020] [Indexed: 12/21/2022]
Abstract
Gluten protein as one of the plant resources is susceptible to genetic, physical, chemical, enzymatic and engineering modifications. Chemical modifications have myriad advantages over other treatments, including short reaction times, low cost, no requirement for specialized equipment, and highly clear modification effects. Therefore, chemical modification of gluten can be mainly conducted via acylation, glycosylation, phosphorylation, and deamidation. The present review investigated the impact of different chemical compounds on conformations of gluten and its subunits. Moreover, their effects on the physico-chemical, morphological, and rheological properties of gluten and their subunits were studied. This allows for the use of gluten for a variety of purposes in the food and non-food industry.
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37
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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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38
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Yilmaz G, Meng FL, Lu W, Abed J, Peh CKN, Gao M, Sargent EH, Ho GW. Autonomous atmospheric water seeping MOF matrix. SCIENCE ADVANCES 2020; 6:eabc8605. [PMID: 33067237 PMCID: PMC7567601 DOI: 10.1126/sciadv.abc8605] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/04/2020] [Indexed: 05/09/2023]
Abstract
The atmosphere contains an abundance of fresh water, but this resource has yet to be harvested efficiently. To date, passive atmospheric water sorbents have required a desorption step that relies on steady solar irradiation. Since the availability and intensity of solar radiation vary, these limit on-demand desorption and hence the amount of harvestable water. Here, we report a polymer-metal-organic framework that provides simultaneous and uninterrupted sorption and release of atmospheric water. The adaptable nature of the hydro-active polymer, and its hybridization with a metal-organic framework, enables enhanced sorption kinetics, water uptake, and spontaneous water oozing. We demonstrate continuous water delivery for 1440 hours, producing 6 g of fresh water per gram of sorbent at 90% relative humidity (RH) per day without active condensation. This leads to a total liquid delivery efficiency of 95% and an autonomous liquid delivery efficiency of 71%, the record among reported atmospheric water harvesters.
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Affiliation(s)
- G Yilmaz
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - F L Meng
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - W Lu
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - J Abed
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, ON M5S 1A4, Canada
- Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, ON M5S 3E4, Canada
| | - C K N Peh
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - M Gao
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - E H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 35 St. George Street, Toronto, ON M5S 1A4, Canada.
| | - G W Ho
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive, Singapore 117575, Singapore
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39
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Cracchiolo OM, Geremia DK, Corcelli SA, Serrano AL. Hydrogen Bond Exchange and Ca2+ Binding of Aqueous N-Methylacetamide Revealed by 2DIR Spectroscopy. J Phys Chem B 2020; 124:6947-6954. [DOI: 10.1021/acs.jpcb.0c02444] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Olivia M. Cracchiolo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Danielle K. Geremia
- 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
| | - Arnaldo L. Serrano
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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40
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The cation effect on the solubility of glycylglycine and N-acetylglycine in aqueous solution: Experimental and molecular dynamics studies. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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41
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Yan X, Chu Y, Liu B, Ru G, Di Y, Feng J. Dynamic mechanism of halide salts on the phase transition of protein models, poly(N-isopropylacrylamide) and poly(N,N-diethylacrylamide). Phys Chem Chem Phys 2020; 22:12644-12650. [PMID: 32458929 DOI: 10.1039/d0cp01366h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of salts on protein systems are not yet fully understood. We investigated the ionic dynamics of three halide salts (NaI, NaBr, and NaCl) with two protein models, namely poly(N-isopropylacrylamide) (PNIPAM) and poly(N,N-diethylacrylamide) (PDEA), using multinuclear NMR, dispersion corrected density functional theory (DFT-D) calculations and dynamic light scattering (DLS) methods. The variation in ionic line-widths and chemical shifts induced by the polymers clearly illustrates that anions rather than cations interact directly with the polymers. From the variable temperature measurements of the NMR transverse relaxation rates of anions, which characterize the polymer-anion interaction intensities, the evolution behaviors of Cl-/Br-/I- during phase transitions are similar in each polymer system but differ between the two polymer systems. The NMR transverse relaxation rates of anions change synchronously with the phase transition of PNIPAM upon heating, but they drop rapidly and vanish about 3-4.5 °C before the phase transition of PDEA. By combining the DFT-D and DLS data, the relaxation results imply that anions escape from the interacting sites with PDEA prior to full polymer dehydration or collapse, which can be attributed to the lack of anion-NH interactions. The different dynamic evolutions of the anions in the PNIPAM and PDEA systems give us an important clue for understanding the micro-mechanism of protein folding in a complex salt aqueous solvent.
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Affiliation(s)
- Xiaoshuang Yan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China.
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Nayak S, Lovering K, Bu W, Uysal A. Anions Enhance Rare Earth Adsorption at Negatively Charged Surfaces. J Phys Chem Lett 2020; 11:4436-4442. [PMID: 32406689 DOI: 10.1021/acs.jpclett.0c01091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Anions are expected to be repelled from negatively charged surfaces. At aqueous interfaces, however, ion-specific effects can dominate over direct electrostatic interactions. Using multiple in situ surface sensitive experimental techniques, we show that surface affinities of SCN- anions are so strong that they can adsorb at a negatively charged floating monolayer at the air-aqueous interface. This extreme example of ion-specific effects may be very important for understanding complex processes at aqueous interfaces, such as chemical separations of rare earth metals. Adsorbed SCN- ions at the floating monolayer increase the overall negative charge density, leading to enhanced trivalent rare earth adsorption. Surface sensitive X-ray fluorescence measurements show that the surface coverage of Lu3+ ions can be triple the apparent surface charge of the floating monolayer in the presence of SCN-. Comparison to NO3- samples shows that the effects are strongly dependent on the character of the anion, providing further evidence of ion-specific effects dominating over electrostatics.
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Affiliation(s)
- Srikanth Nayak
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kaitlin Lovering
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Wei Bu
- NSF's ChemMatCARS, The University of Chicago, Chicago, Illinois 60637, United States
| | - Ahmet Uysal
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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A Shortcut Route to Close Nitrogen Cycle: Bio-Based Amines Production via Selective Deoxygenation of Chitin Monomers over Ru/C in Acidic Solutions. iScience 2020; 23:101096. [PMID: 32422590 PMCID: PMC7229286 DOI: 10.1016/j.isci.2020.101096] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/26/2020] [Accepted: 04/17/2020] [Indexed: 11/21/2022] Open
Abstract
Chitin, a long-chain polymer of N-acetyl-D-glucosamine (NAG) and the most abundant natural nitrogen-containing organic material in the world, is far under-utilized than other biomass resources. Herein, we demonstrate a highly efficient deoxygenation process to convert chitin monomer, i.e., NAG, into various amines, which are the ubiquitous platform chemicals in chemical industry. In the presence of H2 and Ru/C catalyst, the oxygen atoms in the glucosamine molecules are removed in the form of H2O and/or CO/CO2, whereas CO is hydrogenated to CH4. By optimizing the reaction conditions, ∼50% yield of various amines was obtained via the selective deoxygenation of NAG. The reaction mechanism has been proposed. These findings not only promote shell biorefinery in green chemistry and fishery industry but also provide chemicals for material science, resulting in expanding cooperation in new areas such as clean energy, energy conservation, environment protection, and infrastructure. Utilization of the fixed nitrogen from the ocean Greener production of amines and ammonium from chitin Oxygen in glucosamine was removed in the form of H2O and/or CO/CO2 Reaction pathways to produce amines from N-acetyl-D-glucosamine (NAG)
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Revealing the complexity of ionic liquid-protein interactions through a multi-technique investigation. Commun Chem 2020; 3:55. [PMID: 36703418 PMCID: PMC9814843 DOI: 10.1038/s42004-020-0302-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/06/2020] [Indexed: 01/29/2023] Open
Abstract
Ionic liquids offer exciting possibilities for biocatalysis as solvent properties provide rare opportunities for customizable, energy-efficient bioprocessing. Unfortunately, proteins and enzymes are generally unstable in ionic liquids and several attempts have been made to explain why; however, a comprehensive understanding of the ionic liquid-protein interactions remains elusive. Here, we present an analytical framework (circular dichroism (CD), fluorescence, ultraviolet-visible (UV/Vis) and nuclear magnetic resonance (NMR) spectroscopies, and small-angle X-ray scattering (SAXS)) to probe the interactions, structure, and stability of a model protein (green fluorescent protein (GFP)) in a range (acetate, chloride, triflate) of pyrrolidinium and imidazolium salts. We demonstrate that measuring protein stability requires a similar holistic analytical framework, as opposed to single-technique assessments that provide misleading conclusions. We reveal information on site-specific ionic liquid-protein interactions, revealing that triflate (the least interacting anion) induces a contraction in the protein size that reduces the barrier to unfolding. Robust frameworks such as this are critical to advancing non-aqueous biocatalysis and avoiding pitfalls associated with single-technique investigations.
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Park KC, Tsukahara T. Expansion of Ion Effects on Water Induced by a High Hydrophilic Surface of a Polymer Network. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:159-168. [PMID: 31880466 DOI: 10.1021/acs.langmuir.9b02892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The spatial extent and anion-cation cooperativity of the ion effect on the structure and dynamics of water have long been debated but are still controversial. Previously, we experimentally demonstrated the extensive and cooperative effect of ions on water in a polyamide network by measuring the reflection wavelength (λ) on the ion sensor of poly(N-isopropylacrylamide) (PNIPAAm) hydrogel-immobilized photonic crystals. In the present study, we investigated the influence of the polymer surface on the ion effect by adopting a highly hydrophilic poly(N-isopropylacrylamide-co-N-acryloylaza-18-crown-6) hydrogel as a sensor matrix. In alkaline earth metal salt solutions, the copolymer hydrogel membrane sensor showed the redshift of λ for the specific combination of cations and anions, that is, Ca2+/Cl- and Sr2+/NO3-, which resulted from the concerted binding of ion pairs to the copolymer receptor. In alkali metal salt solutions, the ion sensor showed the blueshift of λ originating from the osmotic dehydration suppressed by the salts. The strength of the ion effect was evaluated by the average osmotic pressure (ΠA) required for the salt-inhibited dehydration in the early stage of hydrogel contraction. From the calculation results of ΠA for the copolymer and PNIPAAm hydrogels, it was found that the high hydrophilic copolymer surface more significantly enhanced the ion effect of structure-making cations (i.e., Li+) compared with borderline (Na+) and structure-breaking (K+ and Cs+) cations. Furthermore, the ion effect exhibited the higher ion cooperativity in combination with chloride anions than with nitrate anions. The enhancement of the long-range cooperative ion effect is derived from the expansion of the interactions between ions, water molecules, and the hydrophilic polymer network.
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Affiliation(s)
- Ki Chul Park
- Laboratory for Advanced Nuclear Energy , Institute of Innovative Research, Tokyo Institute of Technology , Tokyo 152-8550 , Japan
| | - Takehiko Tsukahara
- Laboratory for Advanced Nuclear Energy , Institute of Innovative Research, Tokyo Institute of Technology , Tokyo 152-8550 , Japan
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Redman ZC, Tran KH, Parikh SJ, Tjeerdema RS. Influence of pH and Divalent Metals Relevant to California Rice Fields on the Hydroxide-Mediated Hydrolysis of the Insecticide Chlorantraniliprole. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:12402-12407. [PMID: 31663732 DOI: 10.1021/acs.jafc.9b05328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The hydrolysis of chlorantraniliprole (3-bromo-N-[4-chloro-2-methyl-6-(methylcarbamoyl)phenyl]-1-(3-chloro-2-pyridine-2-yl)-1H-pyrazole-5-carboxamide; CAP) was investigated over the pH range of 6-10, reflective of California rice field conditions, with variable additions of Cu2+, Zn2+, Mn2+, or Ni2+. Dissipation accelerated as pH increased with half-lives ranging from 26.9 to 2.2 days with slight inhibition in rice field water. The addition of divalent metals was not observed to catalyze the hydrolysis of CAP at pH 6, indicating that the insecticide is likely to remain recalcitrant to hydrolysis in neutral or acidic surface waters. However, Mn2+ and Ni2+ were observed to inhibit hydrolysis at pH 8 and 9. Attenuated total reflectance Fourier transform infrared analysis supports the conclusion that divalent metals may withdraw electron density from the amide nitrogen via interaction with the amide oxygen, though additional quantum chemical modeling is necessary to provide further mechanistic insights. Overall, the hydrolysis of CAP in California rice fields and their surrounding surface waters will be dominated by pH and inhibited by dissolved metal species.
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Xu F, Yao Y, Alvarez PJ, Li Q, Fu H, Yin D, Zhu D, Qu X. Specific ion effects on the aggregation behavior of aquatic natural organic matter. J Colloid Interface Sci 2019; 556:734-742. [DOI: 10.1016/j.jcis.2019.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 01/29/2023]
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Kashid SM, Singh RK, Kwon H, Kim YS, Mukherjee A, Bagchi S. Arresting an Unusual Amide Tautomer Using Divalent Cations. J Phys Chem B 2019; 123:8419-8424. [PMID: 31532998 DOI: 10.1021/acs.jpcb.9b08463] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ion-specific effects on peptides and proteins are key to biomolecular structure and stability. The subtle roles of the cations are far less understood, compared to the pronounced effects of the anions on proteins. Most importantly, divalent cations such as Ca2+ and Mg2+ are crucial to several biological functions. Herein, we demonstrate that an amide-iminolate equilibrium is triggered by the binding of the divalent cations to the amide oxygen in aqueous solution. The excellent agreement between the experimental and theoretical results confirms the arrest of an unusual amide tautomer by the divalent cations, which is a rarely known phenomenon that might open up an array of applications in chemistry and biology.
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Affiliation(s)
- Somnath M Kashid
- Physical and Materials Chemistry Division , CSIR-National Chemical Laboratory , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad - 201002 , India
| | - Reman K Singh
- Department of Chemistry , Indian Institute of Science Education and Research , Pune 411008 , India
| | - Hyejin Kwon
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil , Ulsan 44919 , Korea
| | - Yung Sam Kim
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil , Ulsan 44919 , Korea
| | - Arnab Mukherjee
- Department of Chemistry , Indian Institute of Science Education and Research , Pune 411008 , India
| | - Sayan Bagchi
- Physical and Materials Chemistry Division , CSIR-National Chemical Laboratory , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad - 201002 , India
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Ghosh S, T D, Baul U, Vemparala S. Aggregation dynamics of charged peptides in water: Effect of salt concentration. J Chem Phys 2019; 151:074901. [DOI: 10.1063/1.5100890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Susmita Ghosh
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Devanand T
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Upayan Baul
- Institue of Physics, Albert-Ludwigs-University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
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50
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The Hofmeister series: Specific ion effects in aqueous polymer solutions. J Colloid Interface Sci 2019; 555:615-635. [PMID: 31408761 DOI: 10.1016/j.jcis.2019.07.067] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/21/2022]
Abstract
Specific ion effects in aqueous polymer solutions have been under active investigation over the past few decades. The current state-of-the-art research is primarily focused on the understanding of the mechanisms through which ions interact with macromolecules and affect their solution stability. Hence, we herein first present the current opinion on the sources of ion-specific effects and review the relevant studies. This includes a summary of the molecular mechanisms through which ions can interact with polymers, quantification of the affinity of ions for the polymer surface, a thermodynamic description of the effects of salts on polymer stability, as well as a discussion on the different forces that contribute to ion-polymer interplay. Finally, we also highlight future research issues that call for further scrutiny. These include fundamental questions on the mechanisms of ion-specific effects and their correlation with polymer properties as well as a discussion on the specific ion effects in more complex systems such as mixed electrolyte solutions.
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