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Le SP, Krishna J, Gupta P, Dutta R, Li S, Chen J, Thayumanavan S. Polymers for Disrupting Protein-Protein Interactions: Where Are We and Where Should We Be? Biomacromolecules 2024; 25:6229-6249. [PMID: 39254158 DOI: 10.1021/acs.biomac.4c00850] [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: 09/11/2024]
Abstract
Protein-protein interactions (PPIs) are central to the cellular signaling and regulatory networks that underlie many physiological and pathophysiological processes. It is challenging to target PPIs using traditional small molecule or peptide-based approaches due to the frequent lack of well-defined binding pockets at the large and flat PPI interfaces. Synthetic polymers offer an opportunity to circumvent these challenges by providing unparalleled flexibility in tuning their physiochemical properties to achieve the desired binding properties. In this review, we summarize the current state of the field pertaining to polymer-protein interactions in solution, highlighting various polyelectrolyte systems, their tunable parameters, and their characterization. We provide an outlook on how these architectures can be improved by incorporating sequence control, foldability, and machine learning to mimic proteins at every structural level. Advances in these directions will enable the design of more specific protein-binding polymers and provide an effective strategy for targeting dynamic proteins, such as intrinsically disordered proteins.
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Affiliation(s)
- Stephanie P Le
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Jithu Krishna
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Prachi Gupta
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Ranit Dutta
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Shanlong Li
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
| | - S Thayumanavan
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Center for Bioactive Delivery, Institute for Applied Life Sciences, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
- Department of Biomedical Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States
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2
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Weimar J, Hirschmann F, Oettel M. Effective patchiness from critical points of a coarse-grained protein model with explicit shape and charge anisotropy. SOFT MATTER 2024. [PMID: 39400290 DOI: 10.1039/d4sm00867g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2024]
Abstract
Colloidal model systems are successful in rationalizing emergent phenomena like aggregation, rheology and phase behaviour of protein solutions. Colloidal theory in conjunction with isotropic interaction models is often employed to estimate the stability of such solutions. In particular, a universal criterion for the reduced second virial coefficient at the critical point is frequently invoked which is based on the behavior of short-range attractive fluids (Noro-Frenkel rule, ). However, if anisotropic models for the protein-protein interaction are considered, e.g. the Kern-Frenkel (KF) patchy particle model, the value of the criterion is shifted to lower values and explicitly depends on the number of patches. If an explicit shape anisotropy is considered, as e.g. in a coarse-grained protein model, the normalization of becomes ambiguous to some extent, as no unique exclusion volume can be defined anymore. Here, we investigate a low-resolution, coarse-grained model for the globular protein bovine serum albumin (BSA) and study effects of charge-anisotropy on the phase diagram (determined by simulations) at the isoelectric point. We present methods of assigning an "effective patchiness" to our protein model by comparing its critical properties to the KF model. We find that doubling the native charges increases the critical temperature Tc by ≈14% and that our BSA model can be compared to a 3 to 5 patch KF model. Finally, we argue that applying existing criteria from colloidal theory should be done with care, due to multiple, physically plausible ways of how to assign effective diameters to shape-anisotropic models.
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Affiliation(s)
- Jens Weimar
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Frank Hirschmann
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Martin Oettel
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
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3
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Giri A, Bhattacharya M. Intrinsic conformational preference in the monomeric protein governs amyloid polymorphism. Phys Chem Chem Phys 2024; 26:25222-25231. [PMID: 39315929 DOI: 10.1039/d4cp01973c] [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: 09/25/2024]
Abstract
The inherent stochasticity associated with the hierarchical self-assembly of either native-like or partially-unfolded protein monomers leads to the formation of transient, morphologically-diverse prefibrillar species resulting in structurally-distinct polymorphic protein aggregates. High-resolution structural characterization of mature aggregates has revealed heterogeneous supramolecular packing of protofibrils within amyloid polymorphs. However, little is known about whether initial monomeric protein conformers engender polymorphism at the onset of aggregation. Here, we show that intrinsic conformational preference in aggregation-competent monomeric ovalbumin, an archetypal serpin, dictates fibrillar polymorphism by modulating aggregation pathways. Using fluorescence, FT-IR, and vibrational Raman spectroscopy coupled with dynamic light scattering and electron microscopy, we demonstrate that conformationally-diverse amyloidogenic monomers, formed via an interplay of electrostatic and hydrophobic interactions before the commencement of aggregation, play a crucial role in promoting amyloid polymorphism. Moreover, the monomeric conformational fingerprints, accrued at the onset of aggregation, persist and propagate during the formation of polymorphic amyloids. Our results delineate essential conformational characteristics of the monomeric protein preceding aggregation, which will have broad implications in the mechanistic understanding of amyloid strain diversity observed in disease-related proteins.
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Affiliation(s)
- Anjali Giri
- Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala-147004, Punjab, India.
| | - Mily Bhattacharya
- Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala-147004, Punjab, India.
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4
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Banks H, Surfaro F, Pastryk KF, Buchholz C, Zaluzhnyy IA, Gerlach A, Schreiber F. From adsorption to crystallization of proteins: Evidence for interface-assisted nucleation. Colloids Surf B Biointerfaces 2024; 241:114063. [PMID: 38954939 DOI: 10.1016/j.colsurfb.2024.114063] [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: 03/05/2024] [Revised: 04/26/2024] [Accepted: 06/25/2024] [Indexed: 07/04/2024]
Abstract
Protein crystallization is among the key processes in biomolecular research, but the underlying mechanisms are still elusive. Here, we address the role of inevitable interfaces for the nucleation process. Quartz crystal microbalance with dissipation monitoring (QCM-D) with simultaneously optical microscopy, confocal microscopy, and grazing-incidence small angle X-rays scattering (GISAXS) were employed to investigate the temporal behavior from the initial stage of protein adsorption to crystallization. Here we studied the crystallization of the Human Serum Albumin (HSA), the most abundant blood protein, in the presence of a charged surface and a trivalent salt. We found evidence for interface-assisted nucleation of crystals. The kinetic stages involved are initial adsorption followed by enhanced adsorption after longer times, subsequent nucleation, and finally crystal growth. The results highlight the importance of interfaces for protein phase behavior and in particular for nucleation.
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Affiliation(s)
- Hadra Banks
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany.
| | - Furio Surfaro
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Kai-Florian Pastryk
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Cara Buchholz
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Ivan A Zaluzhnyy
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Alexander Gerlach
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany; Center for Light-Matter Interaction, Sensors & Analytics LISA+, Auf der Morgenstelle 15, Tübingen 72076, Germany
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5
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Holt C, Carver JA. Invited review: Modeling milk stability. J Dairy Sci 2024; 107:5259-5279. [PMID: 38522835 DOI: 10.3168/jds.2024-24779] [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: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 03/26/2024]
Abstract
Novel insights into the stability of milk and milk products during storage and processing result from describing caseins near neutral pH as hydrophilic, intrinsically disordered, proteins. Casein solubility is strongly influenced by pH and multivalent ion binding. Solubility is high at a neutral pH or above, but decreases as the casein net charge approaches zero, allowing a condensed casein phase or gel to form, then increases at lower pH. Of particular importance for casein micelle stability near neutral pH is the proportion of free caseins in the micelle (i.e., caseins not bound directly to nanoclusters of calcium phosphate). Free caseins are more soluble and better able to act as molecular chaperones (to prevent casein and whey protein aggregation) than bound caseins. Some free caseins are highly phosphorylated and can also act as mineral chaperones to inhibit the growth of calcium phosphate phases and prevent mineralized deposits from forming on membranes or heat exchangers. Thus, casein micelle stability is reduced when free caseins bind to amyloid fibrils, destabilized whey proteins or calcium phosphate. The multivalent-binding model of the casein micelle quantitatively describes these and other factors affecting the stability of milk and milk protein products during manufacture and storage.
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Affiliation(s)
- C Holt
- School of Biomolecular Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
| | - J A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
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6
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Bharmoria P, Tietze AA, Mondal D, Kang TS, Kumar A, Freire MG. Do Ionic Liquids Exhibit the Required Characteristics to Dissolve, Extract, Stabilize, and Purify Proteins? Past-Present-Future Assessment. Chem Rev 2024; 124:3037-3084. [PMID: 38437627 PMCID: PMC10979405 DOI: 10.1021/acs.chemrev.3c00551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 02/08/2024] [Accepted: 02/19/2024] [Indexed: 03/06/2024]
Abstract
Proteins are highly labile molecules, thus requiring the presence of appropriate solvents and excipients in their liquid milieu to keep their stability and biological activity. In this field, ionic liquids (ILs) have gained momentum in the past years, with a relevant number of works reporting their successful use to dissolve, stabilize, extract, and purify proteins. Different approaches in protein-IL systems have been reported, namely, proteins dissolved in (i) neat ILs, (ii) ILs as co-solvents, (iii) ILs as adjuvants, (iv) ILs as surfactants, (v) ILs as phase-forming components of aqueous biphasic systems, and (vi) IL-polymer-protein/peptide conjugates. Herein, we critically analyze the works published to date and provide a comprehensive understanding of the IL-protein interactions affecting the stability, conformational alteration, unfolding, misfolding, and refolding of proteins while providing directions for future studies in view of imminent applications. Overall, it has been found that the stability or purification of proteins by ILs is bispecific and depends on the structure of both the IL and the protein. The most promising IL-protein systems are identified, which is valuable when foreseeing market applications of ILs, e.g., in "protein packaging" and "detergent applications". Future directions and other possibilities of IL-protein systems in light-harvesting and biotechnology/biomedical applications are discussed.
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Affiliation(s)
- Pankaj Bharmoria
- CICECO
- Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
- Department
of Smart Molecular, Inorganic and Hybrid Materials, Institute of Materials Science of Barcelona (ICMAB-CSIC), 08193 Bellaterra, Barcelona, Spain
- Department
of Chemistry and Molecular Biology, Wallenberg Centre for Molecular
and Translational Medicine, University of
Gothenburg, SE-412 96 Göteborg, Sweden
| | - Alesia A. Tietze
- Department
of Chemistry and Molecular Biology, Wallenberg Centre for Molecular
and Translational Medicine, University of
Gothenburg, SE-412 96 Göteborg, Sweden
| | - Dibyendu Mondal
- CICECO
- Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
- Institute
of Plant Genetics (IPG), Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland
- Centre
for Nano and Material Sciences, JAIN (Deemed-to-be
University), Jain Global
Campus, Bangalore 562112, India
| | - Tejwant Singh Kang
- Department
of Chemistry, UGC Center for Advance Studies-II,
Guru Nanak Dev University (GNDU), Amritsar 143005, Punjab, India
| | - Arvind Kumar
- Salt
and Marine Chemicals Division, CSIR-Central
Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar 364002, Gujarat, India
| | - Mara G Freire
- CICECO
- Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
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7
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Saurabh S, Zhang Q, Seddon JM, Lu JR, Kalonia C, Bresme F. Unraveling the Microscopic Mechanism of Molecular Ion Interaction with Monoclonal Antibodies: Impact on Protein Aggregation. Mol Pharm 2024; 21:1285-1299. [PMID: 38345400 PMCID: PMC10915798 DOI: 10.1021/acs.molpharmaceut.3c00963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 03/05/2024]
Abstract
Understanding and predicting protein aggregation represents one of the major challenges in accelerating the pharmaceutical development of protein therapeutics. In addition to maintaining the solution pH, buffers influence both monoclonal antibody (mAb) aggregation in solution and the aggregation mechanisms since the latter depend on the protein charge. Molecular-level insight is necessary to understand the relationship between the buffer-mAb interaction and mAb aggregation. Here, we use all-atom molecular dynamics simulations to investigate the interaction of phosphate (Phos) and citrate (Cit) buffer ions with the Fab and Fc domains of mAb COE3. We demonstrate that Phos and Cit ions feature binding mechanisms, with the protein that are very different from those reported previously for histidine (His). These differences are reflected in distinctive ion-protein binding modes and adsorption/desorption kinetics of the buffer molecules from the mAb surface and result in dissimilar effects of these buffer species on mAb aggregation. While His shows significant affinity toward hydrophobic amino acids on the protein surface, Phos and Cit ions preferentially bind to charged amino acids. We also show that Phos and Cit anions provide bridging contacts between basic amino acids in neighboring proteins. The implications of such contacts and their connection to mAb aggregation in therapeutic formulations are discussed.
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Affiliation(s)
- Suman Saurabh
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College, London W12 0BZ, U.K.
| | - Qinkun Zhang
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College, London W12 0BZ, U.K.
| | - John M. Seddon
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College, London W12 0BZ, U.K.
| | - Jian R. Lu
- Biological
Physics Group, School of Physics and Astronomy, Faculty of Science
and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Cavan Kalonia
- Dosage
Form Design and Development, BioPharmaceutical Development, BioPharmaceuticals
R&D, AstraZeneca, Gaithersburg, Maryland 20878, United States
| | - Fernando Bresme
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College, London W12 0BZ, U.K.
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8
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Belashov AV, Zhikhoreva AA, Gorbunova IA, Sasin ME, Semenova IV, Vasyutinskii OS. Photophysical, rotational and translational properties of Radachlorin photosensitizer upon binding to serum albumins. Biochim Biophys Acta Gen Subj 2024; 1868:130546. [PMID: 38141885 DOI: 10.1016/j.bbagen.2023.130546] [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: 11/03/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
INTRODUCTION Although photophysical properties of Radachlorin photosensitizer (PS) were extensively studied in solutions and cells, no data is available on variations of its characteristics upon binding to serum albumins, which are major transporters in blood and nutrients in cell culture media. OBJECTIVES The primary objective of this study was to analyze changes in photophysical properties of Radachlorin molecules upon their binding to human and bovine serum albumins at different microenvironment properties. METHODS Experiments were performed using time-resolved fluorescence spectroscopy and fluorescence recovery after photobleaching. Variations in fluorescence spectra and lifetime, fluorescence anisotropy, rotational and translational diffusion of PS molecules upon binding to albumins were studied in normal, basic and acidic conditions and at different concentrations of albumin and PS molecules. RESULTS Radachlorin molecules effectively bind to both types of serum albumins, which causes changes in photophysical properties of the PS. A minor red shift of the fluorescence spectrum, an increase in fluorescence lifetime and anisotropy and substantial decrease of translational and rotational mobility of PS molecules were observed upon their binding to albumins. The analysis of rotational diffusion time provided robust evaluation of the bound fraction of PS molecules. Both the highly acidic microenvironment and increase in alcohol concentration above 40% resulted in detachment of PS molecules from albumins. Photophysical properties of Radachlorin in complexes with BSA and HSA were found to be slightly different. CONCLUSIONS Binding of Radachlorin photosensitizer to either BSA or HSA affects significantly its photophysical properties, which may also vary with microenvironment acidity and alcohol concentration.
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Affiliation(s)
- A V Belashov
- Ioffe Institute, 26, Polytekhnicheskaya, St.Petersburg 194021, Russia
| | - A A Zhikhoreva
- Ioffe Institute, 26, Polytekhnicheskaya, St.Petersburg 194021, Russia
| | - I A Gorbunova
- Ioffe Institute, 26, Polytekhnicheskaya, St.Petersburg 194021, Russia
| | - M E Sasin
- Ioffe Institute, 26, Polytekhnicheskaya, St.Petersburg 194021, Russia
| | - I V Semenova
- Ioffe Institute, 26, Polytekhnicheskaya, St.Petersburg 194021, Russia.
| | - O S Vasyutinskii
- Ioffe Institute, 26, Polytekhnicheskaya, St.Petersburg 194021, Russia
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9
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Agrawal NR, Duan C, Wang R. Nature of Overcharging and Charge Inversion in Electrical Double Layers. J Phys Chem B 2024; 128:303-311. [PMID: 38150660 DOI: 10.1021/acs.jpcb.3c04739] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Understanding overcharging and charge inversion is one of the long-standing challenges in soft matter and biophysics. To study these phenomena, we employ the modified Gaussian renormalized fluctuation theory, which allows for the self-consistent accounting of spatially varying ionic strength as well as the spatial variations in dielectric permittivity and excluded volume effects. The underlying dependence of overcharging on the electrostatic coupling is elucidated by varying the surface charge, counterion valency, and dielectric contrast. Consistent with simulations, three characteristic regimes corresponding to weak, moderate, and strong coupling are identified. Important features like the inversion of zeta potential, crowding, and ionic layering at the surface are successfully captured. For weak coupling, there is no overcharging. In the moderate coupling regime, overcharging increases with the surface charge. Finally, in the strong coupling regime, ionic crowding and saturation in overcharging are observed. Our theory predicts a nonmonotonic dependence of charge inversion on multivalent salt concentration as well as the addition of monovalent salt, in quantitative agreement with experiments.
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Affiliation(s)
- Nikhil R Agrawal
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720-1462, United States
| | - Chao Duan
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720-1462, United States
| | - Rui Wang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720-1462, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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10
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Agrawal NR, Kaur R, Carraro C, Wang R. Ion correlation-driven like-charge attraction in multivalent salt solutions. J Chem Phys 2023; 159:244905. [PMID: 38153151 DOI: 10.1063/5.0181061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/06/2023] [Indexed: 12/29/2023] Open
Abstract
The electrostatic double layer force is key to determining the stability and self-assembly of charged colloids and many other soft matter systems. Fully understanding the attractive force between two like-charged surfaces remains a great challenge. Here, we apply the modified Gaussian renormalized fluctuation theory to study ion correlation-driven like-charge attraction in multivalent salt solutions. The effects of spatially varying ion correlations on the structure of overlapping double layers and their free energy are self-consistently accounted for. In the presence of multivalent salts, increasing surface charge or counterion valency leads to a short-range attraction. We demonstrate that although both overcharging and like-charge attraction are outcomes of ion correlation, there is no causal relationship between them. Our theory also captures the non-monotonic dependence of like-charge attraction on multivalent salt concentration. The reduction of attraction at high salt concentrations could be a contributing factor toward the reentrant stability of charged colloidal suspensions. Our theoretical predictions are consistent with the observations reported in experiments and simulations.
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Affiliation(s)
- Nikhil R Agrawal
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
| | - Ravtej Kaur
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
| | - Carlo Carraro
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
| | - Rui Wang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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11
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Senft MD, Maier R, Hiremath A, Zhang F, Schreiber F. Effective interactions and phase behavior of protein solutions in the presence of hexamine cobalt(III) chloride. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:119. [PMID: 38051398 PMCID: PMC10698144 DOI: 10.1140/epje/s10189-023-00376-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023]
Abstract
It is well established that deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) exhibit a reentrant condensation (RC) phase behavior in the presence of the trivalent hexamine cobalt(III) cations (Hac) which can be important for their packing and folding. A similar behavior can be observed for negatively charged globular proteins in the presence of trivalent metal cations, such as Y3+ or La3+. This phase behavior is mainly driven by charge inversion upon an increasing salt concentration for a fixed protein concentration (cp). However, as Hac exhibits structural differences compared to other multivalent metal cations, with six ammonia ligands (NH3) covalently bonded to the central cobalt atom, it is not clear that Hac can induce a similar phase behavior for proteins. In this work, we systematically investigate whether negatively charged globular proteins β-lactoglobulin (BLG), bovine serum albumin (BSA), human serum albumin (HSA) and ovalbumin (OVA) feature Hac-induced RC. Effective protein-protein interactions were investigated by small-angle X-ray scattering. The reduced second virial coefficient (B2/B2HS) was obtained as a function of salt concentration. The virial coefficient analysis performed confirms the reentrant interaction (RI) behavior for BLG without actually inducing RC, given the insufficient strengths of the interactions for the latter to occur. In contrast, the strength of attraction for BSA, HSA and OVA are too weak to show RC. Model free analysis of the inverse intensity [Formula: see text] also supports this finding. Looking at different q-range by employing static (SLS) and dynamic light scattering experiments, the presence of RI behavior can be confirmed. The results are further discussed in view of metal cation binding sites in nucleic acids (DNA and RNA), where Hac induced RC phase behavior.
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Affiliation(s)
- Maximilian D Senft
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany.
| | - Ralph Maier
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Anusha Hiremath
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany.
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
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12
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Wang T, Sun L, Mao X, Du X, Liu J, Chen L, Chen J. Bridging attraction of condensed bovine serum albumin solution in the presence of trivalent ions: A SANS study. Biochim Biophys Acta Gen Subj 2023; 1867:130487. [PMID: 37806463 DOI: 10.1016/j.bbagen.2023.130487] [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: 06/11/2023] [Revised: 09/20/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
The bridging attraction of condensed bovine serum albumin (BSA) solution (D2O) in the presence of yttrium chloride (YCl3) was studied by small angle neutron scattering (SANS). With increasing the concentration of YCl3 (cY) from 3 to 15 mM and from 15 to 100 mM, the intensity in low-q region increases and then decreases. Combining the tri-axial ellipsoid (TaE) geometry and the multi-component sticky hard sphere (SHS) potential, a SHS-TaE model was established to quantitatively determine the size and distribution of particles. In this way, the structural mechanism of the aggregation-redissolution process in protein solution was demonstrated and discussed. As cY increases from 3 to 100 mM, the SHS radius rL decreases from ca. 2.97 to 2.50 nm, suggesting that the relatively well dispersed BSAs may form aggregates with various polydispersities. The axis a increases from 1.88 to 2.30 nm, while b and c decrease from 3.53 to 3.23 nm and from 4.12 to 3.55 nm, respectively. (RgTaE decreases from ca. 2.57 to 2.38 nm). Moreover, the scattering length density (SLD) of BSA decreases from 3.67 to 1.56 × 10-6 Å-2. All these results consistently indicate a strengthened attraction and the BSA molecules might shrink and tune out to be more like of oblate ellipsoid with increasing the amount of YCl3.
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Affiliation(s)
- Tingting Wang
- NHC Key Laboratory of Nuclear Technology Medical Transformation, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang 621000, China.
| | - Liangwei Sun
- Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, 621999 Mianyang, China
| | - Xin Mao
- NHC Key Laboratory of Nuclear Technology Medical Transformation, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang 621000, China
| | - Xiaobo Du
- NHC Key Laboratory of Nuclear Technology Medical Transformation, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang 621000, China.
| | - Jihui Liu
- NHC Key Laboratory of Nuclear Technology Medical Transformation, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang 621000, China
| | - Liang Chen
- Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, 621999 Mianyang, China
| | - Jie Chen
- Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, 621999 Mianyang, China.
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13
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Chi-Uluac LA, Asgharpour S, Blanco-Rodríguez RG, Martínez-Archundia M. Atomistic Molecular Insights into Angiotensin-(1-7) Interpeptide Interactions. J Chem Inf Model 2023; 63:5331-5340. [PMID: 37589289 DOI: 10.1021/acs.jcim.3c00478] [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: 08/18/2023]
Abstract
Angiotensin-(1-7) is an endogenous peptide known for its vasoprotective, antioxidant, and anti-inflammatory effects, making it a promising therapeutic candidate for various clinical conditions. However, the peptide exhibits pH-dependent physical instability in aqueous solutions, and a comprehensive atomistic study elucidating this behavior and its implications is currently lacking. Therefore, we performed all-atom molecular dynamics simulations to investigate the early formation of angiotensin-(1-7) oligomeric aggregates under different conditions: acidic and neutral pH-like conditions, physiological and high ionic strength, and high and low peptide concentrations. Our results are as follows: (1) under acidic pH-like conditions, angiotensin-(1-7) showed minimal clustering, (2) under neutral pH-like conditions, the peptides aggregated into a single cluster, consistent with the reported physical instability, and (3) increasing salt concentration under acidic pH-like conditions resulted in aggregation similar to that observed under neutral pH-like conditions. These results suggest that a combination of salt concentration and pH conditions can modulate angiotensin-(1-7) aggregation. Our protocol (molecular dynamics + cluster analysis + amino acid interaction map analysis) is general and could be applied to other peptides to study interpeptide interaction mechanisms.
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Affiliation(s)
- Luz América Chi-Uluac
- Laboratory for the Design and Development of New Drugs and Biotechnological Innovation, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Ciudad de México 11340, Mexico
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho 83844-1103, United States
| | - Somayeh Asgharpour
- IAS-5/INM-9, Computational Biomedicine, Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany
| | - Rodolfo Guadalupe Blanco-Rodríguez
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho 83844-1103, United States
- Department of Mathematics and Statistical Science, University of Idaho, Moscow, Idaho 83844-1103, United States
| | - Marlet Martínez-Archundia
- Laboratory for the Design and Development of New Drugs and Biotechnological Innovation, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Ciudad de México 11340, Mexico
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14
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Saha D, Jana B. Decoupling of Interactions between Model-Charged Peptides Reveals Key Factors Responsible for Liquid-Liquid Phase Separation. J Phys Chem B 2023; 127:6656-6667. [PMID: 37480340 DOI: 10.1021/acs.jpcb.3c03087] [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: 07/24/2023]
Abstract
Liquid-liquid phase separation (LLPS) by disordered proteins has been shown to govern biological processes and cause numerous diseases. Therefore, a deeper understanding of the interactions and their variation with external factors is key to modulating the LLPS behavior of different systems and protecting proteins from pathological aggregation. In this context, we have looked at interactions between similarly charged peptides to understand the molecular features that may drive or prevent condensate formation under various conditions. We have studied dimer formation for model peptides where charged and noncharged amino acids have been placed alternatively. Using arginine and glutamic acid as the charged residues and varying the other residues with glycine, alanine, and proline to alter hydrophobicity, we have obtained the free-energy surface (FES) for the dimer formation for these systems under high salt concentration at two different temperatures using all-atom molecular dynamics simulations and the well-tempered metadynamics method. Our results indicate that a combination of effects such as hydrophobicity, arginine-arginine interactions, or water release from the solvation shell makes dimerization free energy more favorable for the positively charged peptides with lower flexibility. For the negatively charged peptides, the crucial role of water has been found in governing the FES. Systems having charged residues and phenylalanine in the peptide sequence also have been studied at high salt concentrations using unbiased simulations. In this case, only the positively charged peptides were found to aggregate through temperature-dependent hydrophobic and cation-π interactions. Overall, our study indicates that the negatively charged peptides are more likely to remain in the dilute phase under various conditions compared to the positively charged systems. The findings from our study would be helpful in designing and controlling systems to obtain LLPS behavior for therapeutic usage.
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Affiliation(s)
- Debasis Saha
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
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15
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Glibitskiy D, Gorobchenko O, Nikolov O, Cheipesh T, Dzhimieva T, Zaitseva I, Roshal A, Semenov M, Glibitskiy G. Influence of aluminum and iron chlorides on the parameters of zigzag patterns on films dried from BSA solutions. Sci Rep 2023; 13:9426. [PMID: 37296212 DOI: 10.1038/s41598-023-36515-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023] Open
Abstract
The relationships between the structural and aggregational state of bovine serum albumin (BSA) and the specific length and total number of zigzag pattern segments of the film textures formed upon drying biopolymer solutions with aluminum and iron chlorides have been shown. To obtain films, saline solutions of BSA were dried in a glass cuvette under thermostatically controlled conditions. It is shown that the formation of zigzag structures is sensitive to the influence of aluminum chlorides Al3+ and iron chlorides Fe3+ and depend on the concentration of AlCl3 and FeCl3. This may be due to a change in the charge and size of BSA particles and due to a change in conformation or a violation of the structure of BSA. These factors, in turn, affect the hydration of the solution components and the structural state of free water in solution, which presumably also affects the formation of zigzag structures. It is established that the analysis of the specific length and the number of segments of zigzag patterns makes it possible to evaluate changes in the state of biopolymers in the initial solution during structural changes and aggregation.
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Affiliation(s)
- Dmitriy Glibitskiy
- O. Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12 Academician Proskura Str., Kharkiv, 61085, Ukraine.
| | - Olga Gorobchenko
- V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, 61022, Ukraine
| | - Oleg Nikolov
- V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, 61022, Ukraine
| | - Tatyana Cheipesh
- V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, 61022, Ukraine
| | - Tatyana Dzhimieva
- V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, 61022, Ukraine
| | - Inna Zaitseva
- V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, 61022, Ukraine
- O. M. Beketov National University of Urban Economy in Kharkiv, 17 Marshal Bazhanov Str., Kharkiv, 61002, Ukraine
| | - Alexander Roshal
- Institute for Chemistry, V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, 61022, Ukraine
| | - Mihail Semenov
- O. Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12 Academician Proskura Str., Kharkiv, 61085, Ukraine
| | - Gennadiy Glibitskiy
- O. Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12 Academician Proskura Str., Kharkiv, 61085, Ukraine
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16
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Saha R, Mitra RK. Thermo-Resistive Phase Behavior of Trivalent Ion-Induced Microscopic Protein-Rich Phases: Correlating with Ion-Specific Protein Hydration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4601-4610. [PMID: 36952287 DOI: 10.1021/acs.langmuir.2c03302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Proteins, in the presence of trivalent cations, exhibit intriguing phase behavior which is contrasting compared to mono- and divalent cations. At room temperature (RT), trivalent cations induce microscopic liquid-liquid phase separation (LLPS) in which a protein-rich phase coexists with a dilute phase. The critical solution temperature related phenomena in these complex fluids are well studied; however, such studies have mostly been restricted below the denaturation temperature (TM) of the protein(s) involved. Here, we probe the phase behavior of bovine serum albumin (BSA) incubated at 70 °C (>TM) in the presence of Na+, Mg2+, La3+, Y3+, and Ho3+ ions. BSA in the presence of mono- and bivalent ions forms an intense gel phase at 70 °C; however, the trivalent salts offer remarkable thermal resistivity and retain the fluid LLPS phase. We determine the microscopic phase behavior using differential interference contrast optical microscopy, which shows that the LLPS droplet structures in the M3+ ion-containing protein solutions prevail upon heating, whereas Mg2+ forms composed cross-linking gelation upon thermal incubation. We probe the interior environment of the protein aggregates by ps-resolved fluorescence anisotropy measurements using 8-anilino-1-naphthalenesulfonic acid (ANS) as an extrinsic fluorophore. It reveals that while the LLPS phase retains the rotational time constants upon heating, in the case of gelation, the immediate environment of ANS gets significantly perturbed. We investigate the explicit protein hydration at RT as well as at T > TM using the ATR THz-FTIR (1.5-22.5 THz) spectroscopy technique and found that hydration shows strong ion specificity and correlates the phase transition behavior.
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Affiliation(s)
- Ria Saha
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India
| | - Rajib Kumar Mitra
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India
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17
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Hirschmann F, Lopez H, Roosen-Runge F, Seydel T, Schreiber F, Oettel M. Effects of flexibility in coarse-grained models for bovine serum albumin and immunoglobulin G. J Chem Phys 2023; 158:084112. [PMID: 36859072 DOI: 10.1063/5.0132493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
We construct a coarse-grained, structure-based, low-resolution, 6-bead flexible model of bovine serum albumin (BSA, PDB: 4F5S), which is a popular example of a globular protein in biophysical research. The model is obtained via direct Boltzmann inversion using all-atom simulations of a single molecule, and its particular form is selected from a large pool of 6-bead coarse-grained models using two suitable metrics that quantify the agreement in the distribution of collective coordinates between all-atom and coarse-grained Brownian dynamics simulations of solutions in the dilute limit. For immunoglobulin G (IgG), a similar structure-based 12-bead model has been introduced in the literature [Chaudhri et al., J. Phys. Chem. B 116, 8045 (2012)] and is employed here to compare findings for the compact BSA molecule and the more anisotropic IgG molecule. We define several modified coarse-grained models of BSA and IgG, which differ in their internal constraints and thus account for a variation of flexibility. We study denser solutions of the coarse-grained models with purely repulsive molecules (achievable by suitable salt conditions) and address the effect of packing and flexibility on dynamic and static behavior. Translational and rotational self-diffusivity is enhanced for more elastic models. Finally, we discuss a number of effective sphere sizes for the BSA molecule, which can be defined from its static and dynamic properties. Here, it is found that the effective sphere diameters lie between 4.9 and 6.1 nm, corresponding to a relative spread of about ±10% around a mean of 5.5 nm.
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Affiliation(s)
- Frank Hirschmann
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Hender Lopez
- School of Physics, Clinical and Optometric Sciences, Technological University Dublin, Grangegorman D07 ADY7, Ireland
| | - Felix Roosen-Runge
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Malmö University, 20506 Malmö, Sweden
| | - Tilo Seydel
- Institut Max von Laue-Paul Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Martin Oettel
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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18
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Zalar M, Bye J, Curtis R. Nonspecific Binding of Adenosine Tripolyphosphate and Tripolyphosphate Modulates the Phase Behavior of Lysozyme. J Am Chem Soc 2023; 145:929-943. [PMID: 36608272 PMCID: PMC9853864 DOI: 10.1021/jacs.2c09615] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Adenosine tripolyphosphate (ATP) is a small polyvalent anion that has recently been shown to interact with proteins and have a major impact on assembly processes involved in biomolecular condensate formation and protein aggregation. However, the nature of non-specific protein-ATP interactions and their effects on protein solubility are largely unknown. Here, the binding of ATP to the globular model protein is characterized in detail using X-ray crystallography and nuclear magnetic resonance (NMR). Using NMR, we identified six ATP binding sites on the lysozyme surface, with one known high-affinity nucleic acid binding site and five non-specific previously unknown sites with millimolar affinities that also bind tripolyphosphate (TPP). ATP binding occurs primarily through the polyphosphate moiety, which was confirmed by the X-ray structure of the lysozyme-ATP complex. Importantly, ATP binds preferentially to arginine over lysine in non-specific binding sites. ATP and TPP have similar effects on solution-phase protein-protein interactions. At low salt concentrations, ion binding to lysozyme causes precipitation, while at higher salt concentrations, redissolution occurs. The addition of an equimolar concentration of magnesium to ATP does not alter ATP binding affinities but prevents lysozyme precipitation. These findings have important implications for both protein crystallization and cell biology. Crystallization occurs readily in ATP solutions outside the well-established crystallization window. In the context of cell biology, the findings suggest that ATP binds non-specifically to folded proteins in physiological conditions. Based on the nature of the binding sites identified by NMR, we propose several mechanisms for how ATP binding can prevent the aggregation of natively folded proteins.
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19
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Sarkar S, Kundu S. Effect of different valent ions (Na+, Ca2+ & Y3+) on structural and morphological features of protein (BSA) thin films adsorbed on hydrophobic silicon (H-Si) surface. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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20
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Agrawal NR, Wang R. Self-Consistent Description of Vapor-Liquid Interface in Ionic Fluids. PHYSICAL REVIEW LETTERS 2022; 129:228001. [PMID: 36493445 DOI: 10.1103/physrevlett.129.228001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
Inhomogeneity of ion correlation widely exists in many physicochemical, soft matter, and biological systems. Here, we apply the modified Gaussian renormalized fluctuation theory to study the classic example of the vapor-liquid interface of ionic fluids. The ion correlation is decomposed into a short-range contribution associated with the local electrostatic environment and a long-range contribution accounting for the spatially varying ionic strength and dielectric permittivity. For symmetric salt, both the coexistence curve and the interfacial tension predicted by our theory are in quantitative agreement with simulation data reported in the literature. Furthermore, we provide the first theoretical prediction of interfacial structure for asymmetric salt, highlighting the importance of capturing local charge separation.
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Affiliation(s)
- Nikhil R Agrawal
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
| | - Rui Wang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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21
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Saha R, Mitra RK. Trivalent cation-induced phase separation in proteins: ion specific contribution in hydration also counts. Phys Chem Chem Phys 2022; 24:23661-23668. [PMID: 36148614 DOI: 10.1039/d2cp01061e] [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
Multivalent (specifically trivalent) metal ions are known to induce microscopic phase separation (commonly termed as liquid-liquid phase separation (LLPS)) in negatively charged globular proteins even at ambient temperatures, the process being mostly driven by protein charge neutralization followed by aggregation. Recent simulation studies have revealed that such self-aggregation of proteins is entropy driven; however, it is associated with a solvation effect, which could as well be different from the usual notion of hydrophobic hydration. In this contribution we have experimentally probed the explicit change in hydration associated with ion-induced LLPS formation of a globular protein bovine serum albumin (BSA) at ambient temperature using FIR-THz FTIR spectroscopy (50-750 cm-1; 1.5-22.5 THz). We have used ions of different charges: Na+, K+, Ca2+, Mg2+, La3+, Y3+, Ho3+ and Al3+. We found that all the trivalent ions induce LLPS; the formation of large aggregates has been evidenced from dynamic light scattering (DLS) measurements, but without perturbing the protein structure as confirmed from circular dichroism (CD) measurements. From the frequency dependent absorption coefficient (α(ν)) measurements in the THz frequency domain we estimate the various stretching/vibrational modes of water and we found that ions, forming LLPS, produce definite perturbation in the overall hydration, the extent of which is ion specific, invoking the definite role of hydrophilic (electrostatic) hydration of ions in the observed LLPS process.
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Affiliation(s)
- Ria Saha
- Department of Chemical, Biological & Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences, Block-JD; Sector-III, Salt Lake, Kolkata-700106, India.
| | - Rajib Kumar Mitra
- Department of Chemical, Biological & Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences, Block-JD; Sector-III, Salt Lake, Kolkata-700106, India.
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22
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Pandit S, Kundu S, Aswal VK. Effect of monovalent salts on molecular interactions of globular protein (BSA) above its isoelectric point. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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23
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Pandit S, Kundu S, Aswal VK. Interaction among bovine serum albumin (BSA) molecules in the presence of anions: a small-angle neutron scattering study. J Biol Phys 2022; 48:237-251. [PMID: 35416637 DOI: 10.1007/s10867-022-09608-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/30/2022] [Indexed: 01/01/2023] Open
Abstract
Protein-protein interaction in solution strongly depends on dissolved ions and solution pH. Interaction among globular protein (bovine serum albumin, BSA), above and below of its isoelectric point (pI ≈ 4.8), is studied in the presence of anions (Cl-, Br-, I-, F-, SO42-) using small-angle neutron scattering (SANS) technique. The SANS study reveals that the short-range attraction among BSA molecules remains nearly unchanged in the presence of anions, whereas the intermediate-range repulsive interaction increases following the Hofmeister series of anions. Although the interaction strength modifies below and above the pI of BSA, it nearly follows the series.
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Affiliation(s)
- Subhankar Pandit
- Soft Nano Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Assam, 781035, Garchuk, Guwahati, India
| | - Sarathi Kundu
- Soft Nano Laboratory, Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Assam, 781035, Garchuk, Guwahati, India.
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India
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24
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Effect of Temperature on Re-entrant Condensation of Globular Protein in Presence of Tri-valent Ions. J Fluoresc 2022; 32:791-797. [DOI: 10.1007/s10895-021-02874-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022]
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25
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Sahoo AK, Schreiber F, Netz RR, Maiti PK. Role of entropy in determining the phase behavior of protein solutions induced by multivalent ions. SOFT MATTER 2022; 18:592-601. [PMID: 34928291 DOI: 10.1039/d1sm00730k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Recent experiments have reported lower critical solution temperature (LCST) phase behavior of aqueous solutions of proteins induced by multivalent ions, where the solution phase separates upon heating. This phenomenon is linked to complex hydration effects that result in a net entropy gain upon phase separation. To decipher the underlying molecular mechanism, we use all-atom molecular dynamics simulations along with the two-phase thermodynamic method for entropy calculation. Based on simulations of a single BSA protein in various salt solutions (NaCl, CaCl2, MgCl2, and YCl3) at temperatures (T) ranging 283-323 K, we find that the cation-protein binding affinity increases with T, reflecting its thermodynamic driving force to be entropic in origin. We show that in the cation binding process, many tightly bound water molecules from the solvation shells of a cation and the protein are released to the bulk, resulting in entropy gain. To rationalize the LCST behavior, we calculate the ζ-potential that shows charge inversion of the protein for solutions containing multivalent ions. The ζ-potential increases with T. Performing simulations of two BSA proteins, we demonstrate that the protein-protein binding is mediated by multiple cation bridges and involves similar dehydration effects that cause a large entropy gain which more than compensates for rotational and translational entropy losses of the proteins. Thus, the LCST behavior is entropy-driven, but the associated solvation effects are markedly different from hydrophobic hydration. Our findings have direct implications for tuning the phase behavior of biological and soft-matter systems, e.g., protein condensation and crystallization.
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Affiliation(s)
- Anil Kumar Sahoo
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore-560012, India.
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
- Department of Physics, Indian Institute of Science, Bangalore-560012, India
| | - Prabal K Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore-560012, India.
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26
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Skoda MWA, Conzelmann NF, Fries MR, Reichart LF, Jacobs RMJ, Zhang F, Schreiber F. Switchable β-lactoglobulin (BLG) adsorption on protein resistant oligo (ethylene glycol) (OEG) self-assembled monolayers (SAMs). J Colloid Interface Sci 2022; 606:1673-1683. [PMID: 34534835 DOI: 10.1016/j.jcis.2021.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/07/2021] [Accepted: 08/03/2021] [Indexed: 12/16/2022]
Abstract
HYPOTHESIS Although protein adsorption at an interface is very common and important in biology and biotechnology, it is still not fully understood - mainly due to the intricate balance of forces that ultimately control it. In food processing (and medicine), controlling and manipulating protein adsorption, as well as avoiding protein adsorption (biofilm formation or membrane fouling) by the production of protein-resistant surfaces is of substantial interest. A major factor conferring resistance towards protein adsorption to a surface is the presence of tightly bound water molecules, as is the case in oligo ethylene glycol (OEG)-terminated self-assembled monolayers (SAMs). Due to strong attractive protein-protein and protein-surface interactions observed in systems containing trivalent salt ions, we hypothesize that these conditions may lead to a breakdown of protein resistance in OEG SAMs. EXPERIMENTS We studied the adsorption behavior of BLG in the presence of a lanthanum(III) chloride (LaCl3) at concentrations of 0, 0.1, 0.8 and 5.0 mM on normally protein resistant triethylene glycol-termianted (EG3) SAMs on a gold surface. We used quartz-crystal microbalance with dissipation (QCM-D) and neutron reflectivity (NR) to characterize the morphology of the interfacial region of the SAM. FINDINGS We demonstrate that the protein resistance of the EG3 SAM breaks down beyond a threshold salt concentration c∗ and mirrors the bulk behaviour of this system, showing reduced adsorption beyond a second critical salt concentration c∗∗. These results demonstrate for the first time the controlled switching of the protein-resistant properties of this type of SAM by the addition of trivalent salt.
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Affiliation(s)
- Maximilian W A Skoda
- STFC, ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| | - Nina F Conzelmann
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Madeleine R Fries
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Lara F Reichart
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Robert M J Jacobs
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, South Parks Road, Oxford OX1 3TA, UK
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, Tübingen 72076, Germany.
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27
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Xu X, Jia X, Zhang Y. Dendritic polyelectrolytes with monovalent and divalent counterions: the charge regulation effect and counterion release. SOFT MATTER 2021; 17:10862-10872. [PMID: 34806740 DOI: 10.1039/d1sm01392k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The charge regulation and the release of counterions are extremely important and substantial in determining the charge state of polyelectrolytes and the interaction between polyelectrolytes and proteins. Going beyond monovalent to multivalent cations, it is well-known that the effects of ions are qualitatively different. Therefore, the well-accepted descriptions of the charge regulation and the counterion release based on monovalent ions do not immediately apply to systems with multivalent ions. Here, we study the key structural and electrostatic features of charged dendrimers at hand of the pharmaceutically important dendritic polyglycerol sulfate (dPGS) macromolecule equilibrated with monovalent and divalent salts by molecular dynamics (MD) simulations. Following a simple but accurate scheme to determine its effective radius, the counterion condensed layer of the dPGS is determined with high accuracy and we observe the sequential replacement of condensed monovalent cations (MCs) to divalent cations (DCs) rendering a smaller dPGS effective charge versus the DC concentration. We resolve and track the release of counterions on the dPGS along its binding pathway with the plasma protein Human Serum Albumin (HSA). We find that the release of MCs remains favorable for the complexation leading to a considerable amount of release entropy as the driving force for complexation. The release of DCs only occurs above a certain DC concentration with a comparably smaller number of released ions than MCs. Its contribution to the binding free energy is small indicating a subtle cancellation between the entropy gain in releasing DCs and the enthalpy penalty from dissociating DCs from the dendrimer.
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Affiliation(s)
- Xiao Xu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094, P. R. China.
| | - Xu Jia
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094, P. R. China.
| | - Yuejun Zhang
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094, P. R. China.
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28
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Cheng R, Li J, Ríos de Anda I, Taylor TWC, Faers MA, Anderson JLR, Seddon AM, Royall CP. Protein-polymer mixtures in the colloid limit: Aggregation, sedimentation, and crystallization. J Chem Phys 2021; 155:114901. [PMID: 34551522 DOI: 10.1063/5.0052122] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
While proteins have been treated as particles with a spherically symmetric interaction, of course in reality, the situation is rather more complex. A simple step toward higher complexity is to treat the proteins as non-spherical particles and that is the approach we pursue here. We investigate the phase behavior of the enhanced green fluorescent protein (eGFP) under the addition of a non-adsorbing polymer, polyethylene glycol. From small angle x-ray scattering, we infer that the eGFP undergoes dimerization and we treat the dimers as spherocylinders with aspect ratio L/D - 1 = 1.05. Despite the complex nature of the proteins, we find that the phase behavior is similar to that of hard spherocylinders with an ideal polymer depletant, exhibiting aggregation and, in a small region of the phase diagram, crystallization. By comparing our measurements of the onset of aggregation with predictions for hard colloids and ideal polymers [S. V. Savenko and M. Dijkstra, J. Chem. Phys. 124, 234902 (2006) and Lo Verso et al., Phys. Rev. E 73, 061407 (2006)], we find good agreement, which suggests that the behavior of the eGFP is consistent with that of hard spherocylinders and ideal polymers.
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Affiliation(s)
- Rui Cheng
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Jingwen Li
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | | | - Thomas W C Taylor
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | | | - J L Ross Anderson
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Annela M Seddon
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - C Patrick Royall
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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29
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Fries MR, Skoda MWA, Conzelmann NF, Jacobs RMJ, Maier R, Scheffczyk N, Zhang F, Schreiber F. Bulk phase behaviour vs interface adsorption: Effects of anions and isotopes on β-lactoglobulin (BLG) interactions. J Colloid Interface Sci 2021; 598:430-443. [PMID: 33930747 DOI: 10.1016/j.jcis.2021.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/30/2021] [Accepted: 04/03/2021] [Indexed: 01/17/2023]
Abstract
HYPOTHESIS Protein adsorption is highly relevant in numerous applications ranging from food processing to medical implants. In this context, it is important to gain a deeper understanding of protein-protein and protein-surface interactions. Thus, the focus of this investigation is on the interplay of bulk properties and surface properties on protein adsorption. It was hypothesised that the type of solvent and ions in solution should significantly influence the protein's bulk and interface behaviour, which has been observed in literature and previous work for other net negatively charged, globular proteins such as bovine serum albumin (BSA). EXPERIMENTS The phase behaviour of β-lactoglobulin (BLG) with lanthanum chloride (LaCl3) and iodide (LaI3) in normal water H2O(l) and heavy water (D2O(l)) was established via optical microscopy and ultraviolet-visible spectroscopy. The formation of an adsorption layer and its properties such as thickness, density, structure, and hydration was investigated via neutron reflectivity, quartz-crystal microbalance with dissipation, and infra-red measurements. FINDINGS β-lactoglobulin does not show significant anion-induced or isotope-induced effects - neither in bulk nor at the solid-liquid interface, which deviates strongly from the behaviour of bovine serum albumin. We also provide a comprehensive discussion and comparison of protein-specific bulk and interface behaviour between bovine serum albumin and β-lactoglobulin dependent on anion, cation, solvent, and substrate properties. These findings pave the way for understanding the transition from adsorption to crystallisation.
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Affiliation(s)
- Madeleine R Fries
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
| | - Maximilian W A Skoda
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom.
| | - Nina F Conzelmann
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
| | - Robert M J Jacobs
- Department for Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom.
| | - Ralph Maier
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
| | - Niels Scheffczyk
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
| | - Fajun Zhang
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
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30
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Royall CP, Faers MA, Fussell SL, Hallett JE. Real space analysis of colloidal gels: triumphs, challenges and future directions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:453002. [PMID: 34034239 DOI: 10.1088/1361-648x/ac04cb] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
Colloidal gels constitute an important class of materials found in many contexts and with a wide range of applications. Yet as matter far from equilibrium, gels exhibit a variety of time-dependent behaviours, which can be perplexing, such as an increase in strength prior to catastrophic failure. Remarkably, such complex phenomena are faithfully captured by an extremely simple model-'sticky spheres'. Here we review progress in our understanding of colloidal gels made through the use of real space analysis and particle resolved studies. We consider the challenges of obtaining a suitable experimental system where the refractive index and density of the colloidal particles is matched to that of the solvent. We review work to obtain a particle-level mechanism for rigidity in gels and the evolution of our understanding of time-dependent behaviour, from early-time aggregation to ageing, before considering the response of colloidal gels to deformation and then move on to more complex systems of anisotropic particles and mixtures. Finally we note some more exotic materials with similar properties.
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Affiliation(s)
- C Patrick Royall
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
- HH Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
- School of Chemistry, University of Bristol, Cantock Close, Bristol, BS8 1TS, United Kingdom
- Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, United Kingdom
| | - Malcolm A Faers
- Bayer AG, Crop Science Division, Formulation Technology, Alfred Nobel Str. 50, 40789 Monheim, Germany
| | - Sian L Fussell
- School of Chemistry, University of Bristol, Cantock Close, Bristol, BS8 1TS, United Kingdom
- Bristol Centre for Functional Nanomaterials, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
| | - James E Hallett
- Physical and Theoretical Chemistry Laboratory, South Parks Road, University of Oxford, OX1 3QZ, United Kingdom
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31
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Aledo JC. The Role of Methionine Residues in the Regulation of Liquid-Liquid Phase Separation. Biomolecules 2021; 11:biom11081248. [PMID: 34439914 PMCID: PMC8394241 DOI: 10.3390/biom11081248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 08/12/2021] [Accepted: 08/18/2021] [Indexed: 02/07/2023] Open
Abstract
Membraneless organelles are non-stoichiometric supramolecular structures in the micron scale. These structures can be quickly assembled/disassembled in a regulated fashion in response to specific stimuli. Membraneless organelles contribute to the spatiotemporal compartmentalization of the cell, and they are involved in diverse cellular processes often, but not exclusively, related to RNA metabolism. Liquid-liquid phase separation, a reversible event involving demixing into two distinct liquid phases, provides a physical framework to gain insights concerning the molecular forces underlying the process and how they can be tuned according to the cellular needs. Proteins able to undergo phase separation usually present a modular architecture, which favors a multivalency-driven demixing. We discuss the role of low complexity regions in establishing networks of intra- and intermolecular interactions that collectively control the phase regime. Post-translational modifications of the residues present in these domains provide a convenient strategy to reshape the residue-residue interaction networks that determine the dynamics of phase separation. Focus will be placed on those proteins with low complexity domains exhibiting a biased composition towards the amino acid methionine and the prominent role that reversible methionine sulfoxidation plays in the assembly/disassembly of biomolecular condensates.
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Affiliation(s)
- Juan Carlos Aledo
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
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32
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Kumar S, Saha D, Ray D, Abbas S, Aswal VK. Unusual stability of protein molecules in the presence of multivalent counterions. Phys Rev E 2021; 104:L012603. [PMID: 34412269 DOI: 10.1103/physreve.104.l012603] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 07/08/2021] [Indexed: 12/29/2022]
Abstract
Proteins are known to undergo denaturation and form different phases with varying physicochemical parameters. We report unusual stability of bovine serum albumin protein against commonly used denaturants (temperature and surfactant) in the charged reversal reentrant phase, caused by the multivalent counterions. Unlike monovalent counterions, which promote the denaturants' induced protein unfolding, the unfolding is restricted in the presence of multivalent ions. The observations are beyond the scope of general understanding of protein unfolding and are believed to be governed by ion-ion correlations driven strong condensation of the multivalent ions.
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Affiliation(s)
- Sugam Kumar
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Debasish Saha
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Debes Ray
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sohrab Abbas
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.,Homi Bhabha National Institute, Mumbai 400 094, India
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33
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Uematsu Y. Electrification of water interface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33. [PMID: 34280896 DOI: 10.1088/1361-648x/ac15d5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/19/2021] [Indexed: 05/04/2023]
Abstract
The surface charge of a water interface determines many fundamental processes in physical chemistry and interface science, and it has been intensively studied for over a hundred years. We summarize experimental methods to characterize the surface charge densities developed so far: electrokinetics, double-layer force measurements, potentiometric titration, surface-sensitive nonlinear spectroscopy, and surface-sensitive mass spectrometry. Then, we elucidate physical ion adsorption and chemical electrification as examples of electrification mechanisms. In the end, novel effects on surface electrification are discussed in detail. We believe that this clear overview of state of the art in a charged water interface will surely help the fundamental progress of physics and chemistry at interfaces in the future.
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Affiliation(s)
- Yuki Uematsu
- Department of Physics, Kyushu University, Fukuoka 819-0395, Japan
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34
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Dharan R, Shemesh A, Millgram A, Zalk R, Frank GA, Levi-Kalisman Y, Ringel I, Raviv U. Hierarchical Assembly Pathways of Spermine-Induced Tubulin Conical-Spiral Architectures. ACS NANO 2021; 15:8836-8847. [PMID: 33900736 DOI: 10.1021/acsnano.1c01374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tubulin, an essential cytoskeletal protein, assembles into various morphologies by interacting with an array of cellular factors. One of these factors is the endogenous polyamine spermine, which may promote and stabilize tubulin assemblies. Nevertheless, the assembled structures and their formation pathways are poorly known. Here we show that spermine induced the in vitro assembly of tubulin into several hierarchical architectures based on a tubulin conical-spiral subunit. Using solution X-ray scattering and cryo-TEM, we found that with progressive increase of spermine concentration tubulin dimers assembled into conical-frustum-spirals of increasing length, containing up to three helical turns. The subunits with three helical turns were then assembled into tubules through base-to-top packing and formed antiparallel bundles of tubulin conical-spiral tubules in a distorted hexagonal symmetry. Further increase of the spermine concentration led to inverted tubulin tubules assembled in hexagonal bundles. Time-resolved experiments revealed that tubulin assemblies formed at higher spermine concentrations assembled from intermediates, similar to those formed at low spermine concentrations. These results are distinct from the classical transition between twisted ribbons, helical, and tubular assemblies, and provide insight into the versatile morphologies that tubulin can form. Furthermore, they may contribute to our understanding of the interactions that control the composition and construction of protein-based biomaterials.
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Affiliation(s)
- Raviv Dharan
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Karem, Jerusalem 9112102, Israel
| | - Asaf Shemesh
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Abigail Millgram
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Ran Zalk
- The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Gabriel A Frank
- The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - Yael Levi-Kalisman
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Israel Ringel
- Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Karem, Jerusalem 9112102, Israel
| | - Uri Raviv
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
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35
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Malhotra I, Oyarzún B, Mognetti BM. Unfolding of the chromatin fiber driven by overexpression of noninteracting bridging factors. Biophys J 2021; 120:1247-1256. [PMID: 33453272 PMCID: PMC8059093 DOI: 10.1016/j.bpj.2020.12.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/29/2020] [Accepted: 12/30/2020] [Indexed: 02/05/2023] Open
Abstract
Nuclear molecules control the functional properties of the chromatin fiber by shaping its morphological properties. The biophysical mechanisms controlling how bridging molecules compactify chromatin are a matter of debate. On the one side, bridging molecules could cross-link faraway sites and fold the fiber through the formation of loops. Interacting bridging molecules could also mediate long-range attractions by first tagging different locations of the fiber and then undergoing microphase separation. Using a coarse-grained model and Monte Carlo simulations, we study the conditions leading to compact configurations both for interacting and noninteracting bridging molecules. In the second case, we report on an unfolding transition at high densities of the bridging molecules. We clarify how this transition, which disappears for interacting bridging molecules, is universal and controlled by entropic terms. In general, chains are more compact in the case of interacting bridging molecules because interactions are not valence limited. However, this result is conditional on the ability of our simulation methodology to relax the system toward its ground state. In particular, we clarify how, unless using reaction dynamics that change the length of a loop in a single step, the system is prone to remain trapped in metastable, compact configurations featuring long loops.
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Affiliation(s)
- Isha Malhotra
- Université Libre de Bruxelles, Interdisciplinary Center for Nonlinear Phenomena and Complex Systems, Brussels, Belgium.
| | - Bernardo Oyarzún
- Université Libre de Bruxelles, Interdisciplinary Center for Nonlinear Phenomena and Complex Systems, Brussels, Belgium
| | - Bortolo Matteo Mognetti
- Université Libre de Bruxelles, Interdisciplinary Center for Nonlinear Phenomena and Complex Systems, Brussels, Belgium.
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36
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Lenton S, Hervø-Hansen S, Popov AM, Tully MD, Lund M, Skepö M. Impact of Arginine-Phosphate Interactions on the Reentrant Condensation of Disordered Proteins. Biomacromolecules 2021; 22:1532-1544. [PMID: 33730849 PMCID: PMC8045028 DOI: 10.1021/acs.biomac.0c01765] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Re-entrant condensation results in the formation of a condensed protein regime between two critical ion concentrations. The process is driven by neutralization and inversion of the protein charge by oppositely charged ions. Re-entrant condensation of cationic proteins by the polyvalent anions, pyrophosphate and tripolyphosphate, has previously been observed, but not for citrate, which has similar charge and size compared to the polyphosphates. Therefore, besides electrostatic interactions, other specific interactions between the polyphosphate ions and proteins must contribute. Here, we show that additional attractive interactions between arginine and tripolyphosphate determine the re-entrant condensation and decondensation boundaries of the cationic, intrinsically disordered saliva protein, histatin 5. Furthermore, we show by small-angle X-ray scattering (SAXS) that polyvalent anions cause compaction of histatin 5, as would be expected based solely on electrostatic interactions. Hence, we conclude that arginine-phosphate-specific interactions not only regulate solution properties but also influence the conformational ensemble of histatin 5, which is shown to vary with the number of arginine residues. Together, the results presented here provide further insight into an organizational mechanism that can be used to tune protein interactions in solution of both naturally occurring and synthetic proteins.
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Affiliation(s)
- Samuel Lenton
- Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Stefan Hervø-Hansen
- Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Anton M Popov
- BM29 BIOSAXS, European Synchroton Radiation Facility, 71 avenue des Martyrs, Grenoble, Isère 38043, France
| | - Mark D Tully
- BM29 BIOSAXS, European Synchroton Radiation Facility, 71 avenue des Martyrs, Grenoble, Isère 38043, France
| | - Mikael Lund
- Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.,LINXS-Lund Institute of Advanced Neutron and X-ray Science, Scheelevägen 19, SE-223 70 Lund, Sweden
| | - Marie Skepö
- Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.,LINXS-Lund Institute of Advanced Neutron and X-ray Science, Scheelevägen 19, SE-223 70 Lund, Sweden
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37
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Hazra MK, Levy Y. Biophysics of Phase Separation of Disordered Proteins Is Governed by Balance between Short- And Long-Range Interactions. J Phys Chem B 2021; 125:2202-2211. [PMID: 33629837 PMCID: PMC8028311 DOI: 10.1021/acs.jpcb.0c09975] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Intrinsically disordered proteins
play a crucial role in cellular
phase separation, yet the diverse molecular forces driving phase separation
are not fully understood. It is of utmost importance to understand
how peptide sequence, and particularly the balance between the peptides’
short- and long-range interactions with other peptides, may affect
the stability, structure, and dynamics of liquid–liquid phase
separation in protein condensates. Here, using coarse-grained molecular
dynamics simulations, we studied the liquid properties of the condensate
in a series of polymers in which the ratio of short-range dispersion
interactions to long-range electrostatic interactions varied. As the
fraction of mutations that participate in short-range interactions
increases at the expense of long-range electrostatic interactions,
a significant decrease in the critical temperature of phase separation
is observed. Nevertheless, sequences with a high fraction of short-range
interactions exhibit stabilization, which suggests compensation for
the loss of long-range electrostatic interactions. Decreased condensate
stability is coupled with decreased translational diffusion of the
polymers in the condensate, which may result in the loss of liquid
characteristics in the presence of a high fraction of uncharged residues.
The effect of exchanging long-range electrostatic interactions for
short-range interactions can be explained by the kinetics of breaking
intermolecular contacts with neighboring polymers and the kinetics
of intramolecular fluctuations. While both time scales are coupled
and increase as electrostatic interactions are lost, for sequences
that are dominated by short-range interactions, the kinetics of intermolecular
contact breakage significantly slows down. Our study supports the
contention that different types of interactions can maintain protein
condensates, however, long-range electrostatic interactions enhance
its liquid-like behavior.
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Affiliation(s)
- Milan Kumar Hazra
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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38
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Reentrant liquid condensate phase of proteins is stabilized by hydrophobic and non-ionic interactions. Nat Commun 2021; 12:1085. [PMID: 33597515 PMCID: PMC7889641 DOI: 10.1038/s41467-021-21181-9] [Citation(s) in RCA: 223] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 01/08/2021] [Indexed: 01/31/2023] Open
Abstract
Liquid-liquid phase separation of proteins underpins the formation of membraneless compartments in living cells. Elucidating the molecular driving forces underlying protein phase transitions is therefore a key objective for understanding biological function and malfunction. Here we show that cellular proteins, which form condensates at low salt concentrations, including FUS, TDP-43, Brd4, Sox2, and Annexin A11, can reenter a phase-separated regime at high salt concentrations. By bringing together experiments and simulations, we demonstrate that this reentrant phase transition in the high-salt regime is driven by hydrophobic and non-ionic interactions, and is mechanistically distinct from the low-salt regime, where condensates are additionally stabilized by electrostatic forces. Our work thus sheds light on the cooperation of hydrophobic and non-ionic interactions as general driving forces in the condensation process, with important implications for aberrant function, druggability, and material properties of biomolecular condensates.
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39
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Krainer G, Welsh TJ, Joseph JA, Espinosa JR, Wittmann S, de Csilléry E, Sridhar A, Toprakcioglu Z, Gudiškytė G, Czekalska MA, Arter WE, Guillén-Boixet J, Franzmann TM, Qamar S, George-Hyslop PS, Hyman AA, Collepardo-Guevara R, Alberti S, Knowles TPJ. Reentrant liquid condensate phase of proteins is stabilized by hydrophobic and non-ionic interactions. Nat Commun 2021; 12:1085. [PMID: 33597515 DOI: 10.1101/2020.05.04.076299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 01/08/2021] [Indexed: 05/26/2023] Open
Abstract
Liquid-liquid phase separation of proteins underpins the formation of membraneless compartments in living cells. Elucidating the molecular driving forces underlying protein phase transitions is therefore a key objective for understanding biological function and malfunction. Here we show that cellular proteins, which form condensates at low salt concentrations, including FUS, TDP-43, Brd4, Sox2, and Annexin A11, can reenter a phase-separated regime at high salt concentrations. By bringing together experiments and simulations, we demonstrate that this reentrant phase transition in the high-salt regime is driven by hydrophobic and non-ionic interactions, and is mechanistically distinct from the low-salt regime, where condensates are additionally stabilized by electrostatic forces. Our work thus sheds light on the cooperation of hydrophobic and non-ionic interactions as general driving forces in the condensation process, with important implications for aberrant function, druggability, and material properties of biomolecular condensates.
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Affiliation(s)
- Georg Krainer
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Timothy J Welsh
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Jerelle A Joseph
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Jorge R Espinosa
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Sina Wittmann
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany
| | - Ella de Csilléry
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Akshay Sridhar
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Zenon Toprakcioglu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Giedre Gudiškytė
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Magdalena A Czekalska
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka, 44/52 01-224, Warsaw, Poland
| | - William E Arter
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Jordina Guillén-Boixet
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany
| | - Titus M Franzmann
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany
| | - Seema Qamar
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Peter St George-Hyslop
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- Division of Neurology, Department of Medicine, University of Toronto and University Health Network, Toronto, Ontario, Canada.
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany.
| | - Rosana Collepardo-Guevara
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, UK.
- Department of Genetics, University of Cambridge, Cambridge, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK.
| | - Simon Alberti
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany.
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, UK.
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40
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Bruntha A, Radhipriya R, Palanisamy T, Dhathathreyan A. Elastic compliance and adsorption profiles of Bovine serum albumin at fluid/solid interface in the presence of electrolytes. Biophys Chem 2021; 269:106523. [PMID: 33341694 DOI: 10.1016/j.bpc.2020.106523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/05/2020] [Accepted: 12/07/2020] [Indexed: 11/24/2022]
Abstract
Non-trivial topology of proteins under shear suggests that even small structural changes in proteins result in dramatic variations in the mechanical properties and stability. In this study, we have analysed the elastic compliance of solvated bovine serum albumin (BSA) with NaCl,MgCl2, FeCl3 of concentration-ranging from 50 mM to 250 mM using Quartz crystal microbalance with dissipation. The compliance shows a reverse Hofmeister trend (Na +
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Affiliation(s)
- A Bruntha
- Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - R Radhipriya
- Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India
| | - Thanikaivelan Palanisamy
- Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - A Dhathathreyan
- Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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41
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Suematsu A, Akiyama R. Solvent effect for an effective attraction between like-charged macroions immersed in an electrolyte solution: The intensification mechanism of the effective attraction caused by the translational motion of solvent particles. J Chem Phys 2021; 154:034902. [PMID: 33499638 DOI: 10.1063/5.0033874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The effective interaction between macroanions immersed in an electrolyte solution was calculated using an integral equation theory of liquids to study the solvent granularity effect on the effective attraction mediated by cations. Explicit and implicit solvent models were examined. The effective attraction for the explicit solvent model was found to be stronger than that for the implicit solvent model. This solvent effect was remarkably enhanced only when the effective attraction between macroanions was strong; this means that the solvent effect is not a usual excluded volume effect. The intensification mechanism of the attraction by the solvent granularity is analyzed in the present study, and an indirect mechanism is proposed.
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Affiliation(s)
- Ayumi Suematsu
- Faculty of Science and Engineering, Kyushu Sangyo University, Fukuoka 813-8503, Japan
| | - Ryo Akiyama
- Department of Chemistry, Kyushu University, Fukuoka 812-0395, Japan
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42
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Fries MR, Conzelmann NF, Günter L, Matsarskaia O, Skoda MWA, Jacobs RMJ, Zhang F, Schreiber F. Bulk Phase Behavior vs Interface Adsorption: Specific Multivalent Cation and Anion Effects on BSA Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:139-150. [PMID: 33393312 DOI: 10.1021/acs.langmuir.0c02618] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Proteins are ubiquitous and play a critical role in many areas from living organisms to protein microchips. In humans, serum albumin has a prominent role in the foreign body response since it is the first protein which will interact with, e.g., an implant or stent. In this study, we focused on the influence of salts (i.e., different cations (Y3+, La3+) and anions (Cl-, I-) on bovine serum albumin (BSA) in terms of its bulk behavior as well as the role of charges for protein adsorption at the solid-liquid interface in order to understand and control the underlying molecular mechanisms and interactions. This is part of our group's effort to gain a deeper understanding of protein-protein and protein-surface interactions in the presence of multivalent ions. In the bulk, we established two new phase diagrams and found not only multivalent cation-triggered phase transitions, but also a dependence of the protein behavior on the type of anion. The attractive interactions between proteins were observed to increase from Cl- < NO3- < I-, resulting in iodide preventing re-entrant condensation and promoting liquid-liquid phase separation in bulk. Using ellipsometry and a quartz-crystal microbalance with dissipation (QCM-D), we obtained insight into the growth of the protein adsorption layer. Importantly, we found that phase transitions at the substrate can be triggered by certain interface properties, whether they exist in the bulk solution or not. Through the use of a hydrophilic, negatively charged surface (native silica), the direct binding of anions to the interface was prevented. Interestingly, this led to re-entrant adsorption even in the absence of re-entrant condensation in bulk. However, the overall amount of adsorbed protein was enhanced through stronger attractive protein-protein interactions in the presence of iodide salts. These findings illustrate how carefully chosen surface properties and salts can directly steer the binding of anions and cations, which guide protein behavior, thus paving the way for specific/triggered protein-protein, protein-salt, and protein-surface interactions.
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Affiliation(s)
- Madeleine R Fries
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Nina F Conzelmann
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Luzie Günter
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Olga Matsarskaia
- Institut Max von Laue - Paul Langevin (ILL), CS20156, F-38042 Grenoble, France
| | - Maximilian W A Skoda
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, United Kingdom
| | - Robert M J Jacobs
- Department for Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Fajun Zhang
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen, 72076 Tübingen, Germany
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43
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Statt A, Casademunt H, Brangwynne CP, Panagiotopoulos AZ. Model for disordered proteins with strongly sequence-dependent liquid phase behavior. J Chem Phys 2020; 152:075101. [PMID: 32087632 DOI: 10.1063/1.5141095] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phase separation of intrinsically disordered proteins is important for the formation of membraneless organelles or biomolecular condensates, which play key roles in the regulation of biochemical processes within cells. In this work, we investigated the phase separation of different sequences of a coarse-grained model for intrinsically disordered proteins and discovered a surprisingly rich phase behavior. We studied both the fraction of total hydrophobic parts and the distribution of hydrophobic parts. Not surprisingly, sequences with larger hydrophobic fractions showed conventional liquid-liquid phase separation. The location of the critical point was systematically influenced by the terminal beads of the sequence due to changes in interfacial composition and tension. For sequences with lower hydrophobicity, we observed not only conventional liquid-liquid phase separation but also re-entrant phase behavior in which the liquid phase density decreases at lower temperatures. For some sequences, we observed the formation of open phases consisting of aggregates, rather than a normal liquid. These aggregates had overall lower densities than the conventional liquid phases and exhibited complex geometries with large interconnected string-like or membrane-like clusters. Our findings suggest that minor alterations in the ordering of residues may lead to large changes in the phase behavior of the protein, a fact of significant potential relevance for biology.
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Affiliation(s)
- Antonia Statt
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Helena Casademunt
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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44
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Matsarskaia O, Roosen‐Runge F, Schreiber F. Multivalent ions and biomolecules: Attempting a comprehensive perspective. Chemphyschem 2020; 21:1742-1767. [PMID: 32406605 PMCID: PMC7496725 DOI: 10.1002/cphc.202000162] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/13/2020] [Indexed: 12/13/2022]
Abstract
Ions are ubiquitous in nature. They play a key role for many biological processes on the molecular scale, from molecular interactions, to mechanical properties, to folding, to self-organisation and assembly, to reaction equilibria, to signalling, to energy and material transport, to recognition etc. Going beyond monovalent ions to multivalent ions, the effects of the ions are frequently not only stronger (due to the obviously higher charge), but qualitatively different. A typical example is the process of binding of multivalent ions, such as Ca2+ , to a macromolecule and the consequences of this ion binding such as compaction, collapse, potential charge inversion and precipitation of the macromolecule. Here we review these effects and phenomena induced by multivalent ions for biological (macro)molecules, from the "atomistic/molecular" local picture of (potentially specific) interactions to the more global picture of phase behaviour including, e. g., crystallisation, phase separation, oligomerisation etc. Rather than attempting an encyclopedic list of systems, we rather aim for an embracing discussion using typical case studies. We try to cover predominantly three main classes: proteins, nucleic acids, and amphiphilic molecules including interface effects. We do not cover in detail, but make some comparisons to, ion channels, colloidal systems, and synthetic polymers. While there are obvious differences in the behaviour of, and the relevance of multivalent ions for, the three main classes of systems, we also point out analogies. Our attempt of a comprehensive discussion is guided by the idea that there are not only important differences and specific phenomena with regard to the effects of multivalent ions on the main systems, but also important similarities. We hope to bridge physico-chemical mechanisms, concepts of soft matter, and biological observations and connect the different communities further.
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Affiliation(s)
| | - Felix Roosen‐Runge
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and SocietyMalmö UniversitySweden
- Division of Physical ChemistryLund UniversitySweden
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45
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Valencia L, Nomena EM, Monti S, Rosas-Arbelaez W, Mathew AP, Kumar S, Velikov KP. Multivalent ion-induced re-entrant transition of carboxylated cellulose nanofibrils and its influence on nanomaterials' properties. NANOSCALE 2020; 12:15652-15662. [PMID: 32496493 DOI: 10.1039/d0nr02888f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, we identify and characterize a new intriguing capability of carboxylated cellulose nanofibrils that could be exploited to design smart nanomaterials with tuned response properties for specific applications. Cellulose nanofibrils undergo a multivalent counter-ion induced re-entrant behavior at a specific multivalent metal salt concentration. This effect is manifested as an abrupt increase in the strength of the hydrogel that returns upon a further increment of salt concentration. We systematically study this phenomenon using dynamic light scattering, small-angle X-ray scattering, and molecular dynamics simulations based on a reactive force field. We find that the transitions in the nanofibril microstructure are mainly because of the perturbing actions of multivalent metal ions that induce conformational changes of the nanocellulosic chains and thus new packing arrangements. These new aggregation states also cause changes in the thermal and mechanical properties as well as wettability of the resulting films, upon water evaporation. Our results provide guidelines for the fabrication of cellulose-based films with variable properties by the simple addition of multivalent ions.
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Affiliation(s)
- Luis Valencia
- Division of Materials and Environmental Chemistry, Stockholm University, Frescativägen 8, 10691, Stockholm, Sweden.
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46
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Harada M, Yamamoto S, Yatsuhashi T, Sakota K. Cooperative dissociation of J-aggregates into monomers in the 2-isobutoxyethanol/water binary solvent with the lower critical solution temperature. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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47
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Guzmán E, Fernández-Peña L, Ortega F, Rubio RG. Equilibrium and kinetically trapped aggregates in polyelectrolyte–oppositely charged surfactant mixtures. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2020.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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48
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Gu Q, Li Z, Coffman JL, Przybycien TM, Zydney AL. High throughput solubility and redissolution screening for antibody purification via combined PEG and zinc chloride precipitation. Biotechnol Prog 2020; 36:e3041. [PMID: 32583625 DOI: 10.1002/btpr.3041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/17/2020] [Accepted: 06/15/2020] [Indexed: 01/20/2023]
Abstract
As upstream product titers increase, the downstream chromatographic capture step has become a significant "downstream bottleneck." Precipitation becomes more attractive under these conditions as the supersaturation driving force increases with the ever-increasing titer. In this study, two precipitating reagents with orthogonal mechanisms, polyethylene glycol (PEG) as a volume excluder and zinc chloride (ZnCl2 ) as a cross linker, were examined as precipitants for two monoclonal antibodies (mAbs), one stable and the other aggregation-prone, in purified drug substance and harvested cell culture fluid forms. Manual batch solubility and redissolution experiments were performed as scouting experiments. A high throughput (HTP) liquid handling system was used to investigate the design space as fully as possible while reducing time, labor, and material requirements. Precipitation and redissolution were studied by systematically varying the concentrations of PEG and ZnCl2 to identify combinations that resulted in high yield and good quality for the stable mAb; PEG concentrations in the range 7-7.5 wt/vol% together with 10 mM ZnCl2 gave a yield of 97% and monomer contents of about 93%. While yield for the unstable mAb was high, quality was not acceptable. Performance at selected conditions was further corroborated for the stable mAb using a continuous tubular precipitation reactor at the laboratory scale. The HTP automation system was a powerful tool for locating desired (customized) conditions for antibodies of different physicochemical properties.
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Affiliation(s)
- Qin Gu
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Zhao Li
- Department of Chemical Engineering, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Jonathan L Coffman
- Process Science, Boehringer Ingelheim Pharmaceuticals Inc., Fremont, California, USA
| | - Todd M Przybycien
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Andrew L Zydney
- Department of Chemical Engineering, The Pennsylvania State University, State College, Pennsylvania, USA
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49
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Fries MR, Stopper D, Skoda MWA, Blum M, Kertzscher C, Hinderhofer A, Zhang F, Jacobs RMJ, Roth R, Schreiber F. Enhanced protein adsorption upon bulk phase separation. Sci Rep 2020; 10:10349. [PMID: 32587383 PMCID: PMC7316800 DOI: 10.1038/s41598-020-66562-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/11/2020] [Indexed: 11/08/2022] Open
Abstract
In all areas related to protein adsorption, from medicine to biotechnology to heterogeneous nucleation, the question about its dominant forces and control arises. In this study, we used ellipsometry and quartz-crystal microbalance with dissipation (QCM-D), as well as density-functional theory (DFT) to obtain insight into the mechanism behind a wetting transition of a protein solution. We established that using multivalent ions in a net negatively charged globular protein solution (BSA) can either cause simple adsorption on a negatively charged interface, or a (diverging) wetting layer when approaching liquid-liquid phase separation (LLPS) by changing protein concentration (cp) or temperature (T). We observed that the water to protein ratio in the wetting layer is substantially larger compared to simple adsorption. In the corresponding theoretical model, we treated the proteins as limited-valence (patchy) particles and identified a wetting transition for this complex system. This wetting is driven by a bulk instability introduced by metastable LLPS exposed to an ion-activated attractive substrate.
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Affiliation(s)
- Madeleine R Fries
- Institute for Applied Physics, Auf der Morgenstelle 10, University of Tübingen, 72076, Tübingen, Germany
| | - Daniel Stopper
- Institute for Theoretical Physics, Auf der Morgenstelle 14, University of Tübingen, 72076, Tübingen, Germany
| | - Maximilian W A Skoda
- ISIS Neutron and Muon Source, Science and Technology Facilities Council, Rutherford-Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
| | - Matthias Blum
- Institute for Applied Physics, Auf der Morgenstelle 10, University of Tübingen, 72076, Tübingen, Germany
| | - Christoph Kertzscher
- Institute for Applied Physics, Auf der Morgenstelle 10, University of Tübingen, 72076, Tübingen, Germany
| | - Alexander Hinderhofer
- Institute for Applied Physics, Auf der Morgenstelle 10, University of Tübingen, 72076, Tübingen, Germany
| | - Fajun Zhang
- Institute for Applied Physics, Auf der Morgenstelle 10, University of Tübingen, 72076, Tübingen, Germany
| | - Robert M J Jacobs
- Surface Analysis Facility, Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Roland Roth
- Institute for Theoretical Physics, Auf der Morgenstelle 14, University of Tübingen, 72076, Tübingen, Germany.
| | - Frank Schreiber
- Institute for Applied Physics, Auf der Morgenstelle 10, University of Tübingen, 72076, Tübingen, Germany.
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50
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Begam N, Matsarskaia O, Sztucki M, Zhang F, Schreiber F. Unification of lower and upper critical solution temperature phase behavior of globular protein solutions in the presence of multivalent cations. SOFT MATTER 2020; 16:2128-2134. [PMID: 32016274 DOI: 10.1039/c9sm02329a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In globular protein systems, upper critical solution temperature (UCST) behavior is common, but lower critical solution temperature (LCST) phase transitions are rare. In addition, the temperature sensitivity of such systems is usually difficult to tune. Here we demonstrate that the charge state of globular proteins in aqueous solutions can alter their temperature-dependent phase behavior. We show a universal way to tune the effective protein interactions and induce both UCST and LCST-type transitions in the system using trivalent salts. We provide a phase diagram identifying LCST and UCST regimes as a function of protein and salt concentrations. We further propose a model based on an entropy-driven cation binding mechanism to explain the experimental observations.
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Affiliation(s)
- Nafisa Begam
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany.
| | - Olga Matsarskaia
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany.
| | - Michael Sztucki
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany.
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany.
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