1
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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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2
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Surfaro F, Zhang F, Schreiber F, Roth R. The ion-activated attractive patchy particle model and its application to the liquid-vapor phase transitions. J Chem Phys 2024; 161:034901. [PMID: 39007873 DOI: 10.1063/5.0215920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 06/28/2024] [Indexed: 07/16/2024] Open
Abstract
Patchy particles are an intriguing subject of study and indeed a model system in the field of soft matter physics. In recent years, patchy particle models have been applied to describe a wide variety of systems, including colloidal crystals, macromolecular interactions, liquid crystals, and nanoparticle assemblies. Given the importance of the topic, rationalizing and capturing the basic features of these models is crucial to their correct application in specific systems. In this study, we extend the ion-activated attractive patchy particles model previously employed to elucidate the phase behavior of protein solutions in the presence of trivalent salts. Our extension incorporates the effect of repulsion between unoccupied and occupied binding sites, depicted as patches. Furthermore, we examine the influence of model parameters on the liquid-vapor coexistence region within the phase diagram, employing numerical methods. A deeper understanding of this model will facilitate a better comprehension of the effects observed in experiments.
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Affiliation(s)
- Furio Surfaro
- Institute of Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Fajun Zhang
- Institute of Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institute of Applied Physics, University of Tübingen, 72076 Tübingen, Germany
| | - Roland Roth
- Institute of Theoretical Physics, University of Tübingen, 72076 Tübingen, Germany
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3
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Bagchi D, Maity A, Chakraborty A. Metal Ion-Induced Unusual Stability of the Metastable Vesicle-like Intermediates Evolving during the Self-Assembly of Phenylalanine: Prominent Role of Surface Charge Inversion. J Phys Chem Lett 2024; 15:4468-4476. [PMID: 38631022 DOI: 10.1021/acs.jpclett.4c00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
The underlying mechanism and intermediate formation in the self-assembly of aromatic amino acids, peptides, and proteins remain elusive despite numerous reports. We, for the first time, report that one can stabilize the intermediates by tuning the metal ion-amino acid interaction. Microscopic and spectroscopic investigations of the self-assembly of carboxybenzyl (Z)-protected phenylalanine (ZF) reveal that the bivalent metal ions eventually lead to the formation of fibrillar networks similar to blank ZF whereas the trivalent ions develop vesicle-like intermediates that do not undergo fibrillation for a prolonged time. The time-lapse measurement of surface charge reveals that the surface charge of blank ZF and in the presence of bivalent metal ions changes from a negative value to zero, implying unstable intermediates leading to the fibril network. Strikingly, a prominent charge inversion from an initial negative value to a positive value in the presence of trivalent metal ions imparts unusual stability to the metastable intermediates.
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Affiliation(s)
- Debanjan Bagchi
- Indian Institute of Technology Indore, Department of Chemistry, Indore 453552, Madhya Pradesh, India
| | - Avijit Maity
- Indian Institute of Technology Indore, Department of Chemistry, Indore 453552, Madhya Pradesh, India
| | - Anjan Chakraborty
- Indian Institute of Technology Indore, Department of Chemistry, Indore 453552, Madhya Pradesh, India
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4
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Rozhkov S, Goryunov A, Rozhkova N. Molecular Serum Albumin Unmask Nanobio Properties of Molecular Graphenes in Shungite Carbon Nanoparticles. Int J Mol Sci 2024; 25:2465. [PMID: 38473711 DOI: 10.3390/ijms25052465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/11/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
Serum albumin is a popular macromolecule for studying the effect of proteins on the colloidal stability of nanoparticle (NP) dispersions, as well as the protein-nanoparticle interaction and protein corona formation. In this work, we analyze the specific conformation-dependent phase, redox, and fatty acid delivery properties of bovine albumin in the presence of shungite carbon (ShC) molecular graphenes stabilized in aqueous dispersions in the form of NPs in order to reveal the features of NP bioactivity. The formation of NP complexes with proteins (protein corona around NP) affects the transport properties of albumin for the delivery of fatty acids. Being acceptors of electrons and ligands, ShC NPs are capable of exhibiting both their own biological activity and significantly affecting conformational and phase transformations in protein systems.
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Affiliation(s)
- Sergey Rozhkov
- Institute of Biology, Karelian Research Centre RAS, 185910 Petrozavodsk, Russia
| | - Andrey Goryunov
- Institute of Biology, Karelian Research Centre RAS, 185910 Petrozavodsk, Russia
| | - Natalia Rozhkova
- Institute of Geology, Karelian Research Centre RAS, 185910 Petrozavodsk, Russia
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5
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Paul B, Furst EM, Lenhoff AM, Wagner NJ, Teixeira SCM. Combined Effects of Pressure and Ionic Strength on Protein-Protein Interactions: An Empirical Approach. Biomacromolecules 2024; 25:338-348. [PMID: 38117685 DOI: 10.1021/acs.biomac.3c01001] [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] [Indexed: 12/22/2023]
Abstract
Proteins are exposed to hydrostatic pressure (HP) in a variety of ecosystems as well as in processing steps such as freeze-thaw, cell disruption, sterilization, and homogenization, yet pressure effects on protein-protein interactions (PPIs) remain underexplored. With the goal of contributing toward the expanded use of HP as a fundamental control parameter in protein research, processing, and engineering, small-angle X-ray scattering was used to examine the effects of HP and ionic strength on ovalbumin, a model protein. Based on an extensive data set, we develop an empirical method for scaling PPIs to a master curve by combining HP and osmotic effects. We define an effective pressure parameter that has been shown to successfully apply to other model protein data available in the literature, with deviations evident for proteins that do not follow the apparent Hofmeister series. The limitations of the empirical scaling are discussed in the context of the hypothesized underlying mechanisms.
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Affiliation(s)
- Brian Paul
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Eric M Furst
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Abraham M Lenhoff
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Norman J Wagner
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Susana C M Teixeira
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
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6
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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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7
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Crabtree MD, Holland J, Pillai AS, Kompella PS, Babl L, Turner NN, Eaton JT, Hochberg GKA, Aarts DGAL, Redfield C, Baldwin AJ, Nott TJ. Ion binding with charge inversion combined with screening modulates DEAD box helicase phase transitions. Cell Rep 2023; 42:113375. [PMID: 37980572 PMCID: PMC10935546 DOI: 10.1016/j.celrep.2023.113375] [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: 03/10/2023] [Revised: 07/14/2023] [Accepted: 10/18/2023] [Indexed: 11/21/2023] Open
Abstract
Membraneless organelles, or biomolecular condensates, enable cells to compartmentalize material and processes into unique biochemical environments. While specific, attractive molecular interactions are known to stabilize biomolecular condensates, repulsive interactions, and the balance between these opposing forces, are largely unexplored. Here, we demonstrate that repulsive and attractive electrostatic interactions regulate condensate stability, internal mobility, interfaces, and selective partitioning of molecules both in vitro and in cells. We find that signaling ions, such as calcium, alter repulsions between model Ddx3 and Ddx4 condensate proteins by directly binding to negatively charged amino acid sidechains and effectively inverting their charge, in a manner fundamentally dissimilar to electrostatic screening. Using a polymerization model combined with generalized stickers and spacers, we accurately quantify and predict condensate stability over a wide range of pH, salt concentrations, and amino acid sequences. Our model provides a general quantitative treatment for understanding how charge and ions reversibly control condensate stability.
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Affiliation(s)
- Michael D Crabtree
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Jack Holland
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Arvind S Pillai
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Purnima S Kompella
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Leon Babl
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Noah N Turner
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - James T Eaton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK; Kavli Insititute of Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, Sherrington Rd, Oxford, OX1 3QU, UK
| | - Georg K A Hochberg
- Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany; Center for Synthetic Microbiology, Philipps University Marburg, Karl-von-Frisch-Straße 14, 35032 Marburg, Germany
| | - Dirk G A L Aarts
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Andrew J Baldwin
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK; Kavli Insititute of Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, Sherrington Rd, Oxford, OX1 3QU, UK.
| | - Timothy J Nott
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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8
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Matyushov DV. Nonlinear dielectric response of dilute protein solutions. RSC Adv 2023; 13:31123-31127. [PMID: 37881764 PMCID: PMC10594618 DOI: 10.1039/d3ra06033k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 10/19/2023] [Indexed: 10/27/2023] Open
Abstract
A theory for the nonlinear dielectric response of dilute protein solutions is presented. The field-dependent dielectric function of the protein solution changes linearly with the electric field squared in the lowest order. The slope of this dependence is expressed in terms of the protein dipole moment M0, its volume fraction in solution η0, and the second osmotic virial coefficient. For practical conditions, the nonlinear dielectric response scales as η03M08. This strong dependence on the protein dipole moment and concentration establishes a sharp contrast between the nonlinear response of solvated proteins relative to the surrounding polar solvent. Nonlinear dielectric response can serve as a sensitive tool for monitoring protein conformations and physiological activity.
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Affiliation(s)
- Dmitry V Matyushov
- School of Molecular Sciences, Department of Physics, Arizona State University PO Box 871504 Tempe Arizona 85287-1504 USA
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9
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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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10
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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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11
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Jakob LA, Mesurado T, Jungbauer A, Lingg N. Increase in cysteine-mediated multimerization under attractive protein-protein interactions. Prep Biochem Biotechnol 2022; 53:891-905. [PMID: 36576211 DOI: 10.1080/10826068.2022.2158471] [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] [Indexed: 12/29/2022]
Abstract
The CASPON enzyme became an interesting enzyme for fusion protein processing because it generates an authentic N-terminus. However, the high cysteine content of the CASPON enzyme may induce aggregation via disulfide-bond formation, which can reduce enzymatic activity and be considered a critical quality attribute. Different multimerization states of the CASPON enzyme were isolated by preparative size exclusion chromatography and analyzed with respect to multimerization propensity and enzymatic activity. The impact of co-solutes on multimerization was studied in solution and in adsorbed state. Furthermore, protein-protein interactions in the presence of different co-solutes were measured by self-interaction chromatography and were then correlated to the multimerization propensity. The dimer was the most stable and active species with 50% higher enzymatic activity than the tetramer. Multimerization was mainly governed by a cysteine-mediated pathway, as indicated by DTT-induced reduction of most caspase multimers. In the presence of ammonium sulfate, attractive protein-protein interactions were consistent with those observed for higher multimerization when the cysteine-mediated pathway was followed. Multimerization was also observed under attractive conditions on a chromatographic stationary phase. These findings corroborate common rules to perform protein purification with low residence time to avoid disulfide bond formation and conformational change of the protein upon adsorption.
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Affiliation(s)
- Leo A Jakob
- Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Tomás Mesurado
- Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Alois Jungbauer
- Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Austria
- Austrian Centre of Industrial Biotechnology, Vienna, Austria
| | - Nico Lingg
- Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Austria
- Austrian Centre of Industrial Biotechnology, Vienna, Austria
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12
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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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13
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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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14
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Hansen J, Pedersen JN, Pedersen JS, Egelhaaf SU, Platten F. Universal effective interactions of globular proteins close to liquid–liquid phase separation: Corresponding-states behavior reflected in the structure factor. J Chem Phys 2022; 156:244903. [DOI: 10.1063/5.0088601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Intermolecular interactions in protein solutions, in general, contain many contributions. If short-range attractions dominate, the state diagram exhibits liquid–liquid phase separation (LLPS) that is metastable with respect to crystallization. In this case, the extended law of corresponding states (ELCS) suggests that thermodynamic properties are insensitive to details of the underlying interaction potential. Using lysozyme solutions, we investigate the applicability of the ELCS to the static structure factor and how far effective colloidal interaction models can help to rationalize the phase behavior and interactions of protein solutions in the vicinity of the LLPS binodal. The (effective) structure factor has been determined by small-angle x-ray scattering. It can be described by Baxter’s adhesive hard-sphere model, which implies a single fit parameter from which the normalized second virial coefficient b2 is inferred and found to quantitatively agree with previous results from static light scattering. The b2 values are independent of protein concentration but systematically vary with temperature and solution composition, i.e., salt and additive content. If plotted as a function of temperature normalized by the critical temperature, the values of b2 follow a universal behavior. These findings validate the applicability of the ELCS to globular protein solutions and indicate that the ELCS can also be reflected in the structure factor.
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Affiliation(s)
- Jan Hansen
- Heinrich Heine University, Condensed Matter Physics Laboratory, Düsseldorf, Germany
| | - Jannik N. Pedersen
- iNANO Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jan Skov Pedersen
- iNANO Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Stefan U. Egelhaaf
- Heinrich Heine University, Condensed Matter Physics Laboratory, Düsseldorf, Germany
| | - Florian Platten
- Heinrich Heine University, Condensed Matter Physics Laboratory, Düsseldorf, Germany
- Forschungszentrum Jülich, Institute of Biological Information Processing IBI-4, Biomacromolecular Systems and Processes, Jülich, Germany
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15
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Hartl J, Friesen S, Johannsmann D, Buchner R, Hinderberger D, Blech M, Garidel P. Dipolar Interactions and Protein Hydration in Highly Concentrated Antibody Formulations. Mol Pharm 2022; 19:494-507. [PMID: 35073097 DOI: 10.1021/acs.molpharmaceut.1c00587] [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] [Indexed: 12/16/2022]
Abstract
Molecular interaction mechanisms in high-concentrated protein systems are of fundamental importance for the rational development of biopharmaceuticals such as monoclonal antibody (mAb) formulations. In such high-concentrated protein systems, the intermolecular distances between mAb molecules are reduced to the size of the protein diameter (approx. 10 nm). Thus, protein-protein interactions are more pronounced at high concentrations; so a direct extrapolation of physicochemical properties obtained from measurements at a low protein concentration of the corresponding properties at a high protein concentration is highly questionable. Besides the charge-charge interaction, the effects of molecular crowding, dipolar interaction, changes in protein hydration, and self-assembling tendency become more relevant. Here, protein hydration, protein dipole moment, and protein-protein interactions were studied in protein concentrations up to 200 mg/mL (= 1.3 mM) in different formulations for selected mAbs using dielectric relaxation spectroscopy (DRS). These data are correlated with the second virial coefficient, A2, the diffusion interaction parameter, kD, the elastic shear modulus, G', and the dynamic viscosity, η. When large contributions of dipolar protein-protein interactions were observed, the tendency of self-assembling and an increase in solution viscosity were detected. These effects were examined using specific buffer conditions. Furthermore, different types of protein-water interactions were identified via DRS, whereby the effect of high protein concentration on protein hydration was investigated for different high-concentrated liquid formulations (HCLFs).
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Affiliation(s)
- Josef Hartl
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Sergej Friesen
- Institute of Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Diethelm Johannsmann
- Institute of Physical Chemistry, Clausthal University of Technology, 38678 Clausthal-Zellerfeld, Germany
| | - Richard Buchner
- Institute of Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Dariush Hinderberger
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Michaela Blech
- Boehringer Ingelheim Pharma GmbH & Co. KG, Innovation Unit, PDB, 88397 Biberach an der Riss, Germany
| | - Patrick Garidel
- Boehringer Ingelheim Pharma GmbH & Co. KG, Innovation Unit, PDB, 88397 Biberach an der Riss, Germany
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16
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Beck C, Grimaldo M, Braun MK, Bühl L, Matsarskaia O, Jalarvo NH, Zhang F, Roosen-Runge F, Schreiber F, Seydel T. Temperature and salt controlled tuning of protein clusters. SOFT MATTER 2021; 17:8506-8516. [PMID: 34490428 DOI: 10.1039/d1sm00418b] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The formation of molecular assemblies in protein solutions is of strong interest both from a fundamental viewpoint and for biomedical applications. While ordered and desired protein assemblies are indispensable for some biological functions, undesired protein condensation can induce serious diseases. As a common cofactor, the presence of salt ions is essential for some biological processes involving proteins, and in aqueous suspensions of proteins can also give rise to complex phase diagrams including homogeneous solutions, large aggregates, and dissolution regimes. Here, we systematically study the cluster formation approaching the phase separation in aqueous solutions of the globular protein BSA as a function of temperature (T), the protein concentration (cp) and the concentrations of the trivalent salts YCl3 and LaCl3 (cs). As an important complement to structural, i.e. time-averaged, techniques we employ a dynamical technique that can detect clusters even when they are transient on the order of a few nanoseconds. By employing incoherent neutron spectroscopy, we unambiguously determine the short-time self-diffusion of the protein clusters depending on cp, cs and T. We determine the cluster size in terms of effective hydrodynamic radii as manifested by the cluster center-of-mass diffusion coefficients D. For both salts, we find a simple functional form D(cp, cs, T) in the parameter range explored. The calculated inter-particle attraction strength, determined from the microscopic and short-time diffusive properties of the samples, increases with salt concentration and temperature in the regime investigated and can be linked to the macroscopic behavior of the samples.
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Affiliation(s)
- Christian Beck
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042 Grenoble, France.
| | - Marco Grimaldo
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042 Grenoble, France.
| | - Michal K Braun
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Lena Bühl
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Olga Matsarskaia
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042 Grenoble, France.
| | - Niina H Jalarvo
- Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
- Chemical and Engineering Materials Division, Neutron Sciences Directorate, and JCNS Outstation at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, USA
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Felix Roosen-Runge
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Malmö University, 20506 Malmö, Sweden.
- Division of Physical Chemistry, Lund University, Naturvetarvägen 14, 22100 Lund, Sweden
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Tilo Seydel
- Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042 Grenoble, France.
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17
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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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18
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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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19
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Bramham JE, Davies SA, Podmore A, Golovanov AP. Stability of a high-concentration monoclonal antibody solution produced by liquid-liquid phase separation. MAbs 2021; 13:1940666. [PMID: 34225583 PMCID: PMC8265796 DOI: 10.1080/19420862.2021.1940666] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Subcutaneous injection of a low volume (<2 mL) high concentration (>100 mg/mL) formulation is an attractive administration strategy for monoclonal antibodies (mAbs) and other biopharmaceutical proteins. Using concentrated solutions may also be beneficial at various stages of bioprocessing. However, concentrating proteins by conventional techniques, such as ultrafiltration, can be time consuming and challenging. Isolation of the dense fraction produced by macroscopic liquid–liquid phase separation (LLPS) has been suggested as a means to produce high-concentration solutions, but practicality of this method, and the stability of the resulting protein solution have not previously been demonstrated. In this proof-of-concept study, we demonstrate that LLPS can be used to concentrate a mAb solution to >170 mg/mL. We show that the structure of the mAb is not altered by LLPS, and unperturbed mAb is recoverable following dilution of the dense fraction, as judged by 1H nuclear magnetic resonance spectroscopy. Finally, we show that the physical properties and stability of a model high concentration protein formulation obtained from the dense fraction can be improved, for example through the addition of the excipient arginine·glutamate. This results in a stable high-concentration protein formulation with reduced viscosity and no further macroscopic LLPS. Concentrating mAb solutions by LLPS represents a simple and effective technique to progress toward producing high-concentration protein formulations for bioprocessing or administration. Abbreviations Arginine·glutamate (Arg·Glu), Carr-Purcell-Meiboom-Gill (CPMG), critical temperature (TC), high-performance size-exclusion chromatography (HPSEC), liquid–liquid phase separation (LLPS), monoclonal antibody (mAb), nuclear magnetic resonance (NMR), transverse relaxation rate (R2)
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Affiliation(s)
- Jack E Bramham
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
| | - Stephanie A Davies
- Dosage Form Design & Development, BioPharmaceuticals Development, R&D, AstraZeneca, Cambridge, UK
| | - Adrian Podmore
- Dosage Form Design & Development, BioPharmaceuticals Development, R&D, AstraZeneca, Cambridge, UK
| | - Alexander P Golovanov
- Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
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20
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Kalayan J, Curtis RA, Warwicker J, Henchman RH. Thermodynamic Origin of Differential Excipient-Lysozyme Interactions. Front Mol Biosci 2021; 8:689400. [PMID: 34179093 PMCID: PMC8226134 DOI: 10.3389/fmolb.2021.689400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/25/2021] [Indexed: 01/15/2023] Open
Abstract
Understanding the intricate interplay of interactions between proteins, excipients, ions and water is important to achieve the effective purification and stable formulation of protein therapeutics. The free energy of lysozyme interacting with two kinds of polyanionic excipients, citrate and tripolyphosphate, together with sodium chloride and TRIS-buffer, are analysed in multiple-walker metadynamics simulations to understand why tripolyphosphate causes lysozyme to precipitate but citrate does not. The resulting multiscale decomposition of energy and entropy components for water, sodium chloride, excipients and lysozyme reveals that lysozyme is more stabilised by the interaction of tripolyphosphate with basic residues. This is accompanied by more sodium ions being released into solution from tripolyphosphate than for citrate, whilst the latter instead has more water molecules released into solution. Even though lysozyme aggregation is not directly probed in this study, these different mechanisms are suspected to drive the cross-linking between lysozyme molecules with vacant basic residues, ultimately leading to precipitation.
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Affiliation(s)
- Jas Kalayan
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom.,Department of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Robin A Curtis
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom.,Departments of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, United Kingdom
| | - Jim Warwicker
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom.,Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Richard H Henchman
- Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom.,Department of Chemistry, The University of Manchester, Manchester, United Kingdom.,Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
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21
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Jakob LA, Beyer B, Janeiro Ferreira C, Lingg N, Jungbauer A, Tscheließnig R. Protein-protein interactions and reduced excluded volume increase dynamic binding capacity of dual salt systems in hydrophobic interaction chromatography. J Chromatogr A 2021; 1649:462231. [PMID: 34038776 DOI: 10.1016/j.chroma.2021.462231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 10/21/2022]
Abstract
Deploying two salts in hydrophobic interaction chromatography can significantly increase dynamic binding capacities. Nevertheless, the mechanistic understanding of this phenomenon is lacking. Here, we investigate whether surface tension or ionic strength govern dynamic binding capacities of the chromatographic resin Toyopearl Butyl-650 M in dual salt systems. Small-angle X-ray scattering was employed to analyze the model proteins and the protein-resin adduct in the respective dual salt systems. The dual salt systems incorporate sodium citrate and a secondary sodium salt (acetate, sulfate, or phosphate). As model proteins, we used lysozyme, GFP, and a monoclonal antibody (adalimumab). Moreover, for the protein-resin adduct, we determined the model parameters of a self-avoiding random walk model fitted into the pair density distribution function of the SAXS data. Ionic strength is more predictive for dynamic binding capacities in HIC dual salt systems than surface tension. However, dynamic binding capacities still differ by up to 30 % between the investigated dual salt systems. The proteins exhibit extensive protein-protein interactions in the studied dual salt HIC buffers. We found a correlation of protein-protein interactions with the well-known Hofmeister series. For systems with elevated protein-protein interactions, adsorption isotherms deviate from Langmuirian behavior. This highlights the importance of lateral protein-protein interactions in protein adsorption, where monomolecular protein layers are usually assumed. SAXS analysis of the protein-resin adduct indicates an inverse correlation of the binding capacity and the excluded volume parameter. This is indicative of the deposition of proteins in the cavities of the stationary phase. We hypothesize that increasing protein-protein interactions allow the formation of attractive clusters and multilayers in the cavities, respectively.
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Affiliation(s)
- Leo A Jakob
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190, Austria
| | - Beate Beyer
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190, Austria; Austrian Centre of Industrial Biotechnology, Muthgasse 18, Vienna A-1190, Austria
| | | | - Nico Lingg
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190, Austria; Austrian Centre of Industrial Biotechnology, Muthgasse 18, Vienna A-1190, Austria
| | - Alois Jungbauer
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190, Austria; Austrian Centre of Industrial Biotechnology, Muthgasse 18, Vienna A-1190, Austria.
| | - Rupert Tscheließnig
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, A-1190, Austria
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22
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Van Lindt J, Bratek-Skicki A, Nguyen PN, Pakravan D, Durán-Armenta LF, Tantos A, Pancsa R, Van Den Bosch L, Maes D, Tompa P. A generic approach to study the kinetics of liquid-liquid phase separation under near-native conditions. Commun Biol 2021; 4:77. [PMID: 33469149 PMCID: PMC7815728 DOI: 10.1038/s42003-020-01596-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 11/30/2020] [Indexed: 11/09/2022] Open
Abstract
Understanding the kinetics, thermodynamics, and molecular mechanisms of liquid-liquid phase separation (LLPS) is of paramount importance in cell biology, requiring reproducible methods for studying often severely aggregation-prone proteins. Frequently applied approaches for inducing LLPS, such as dilution of the protein from an urea-containing solution or cleavage of its fused solubility tag, often lead to very different kinetic behaviors. Here we demonstrate that at carefully selected pH values proteins such as the low-complexity domain of hnRNPA2, TDP-43, and NUP98, or the stress protein ERD14, can be kept in solution and their LLPS can then be induced by a jump to native pH. This approach represents a generic method for studying the full kinetic trajectory of LLPS under near native conditions that can be easily controlled, providing a platform for the characterization of physiologically relevant phase-separation behavior of diverse proteins.
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Affiliation(s)
- Joris Van Lindt
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Anna Bratek-Skicki
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium. .,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
| | - Phuong N Nguyen
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Biology, College of Natural Sciences, Cantho University, Can Tho, Vietnam
| | - Donya Pakravan
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium
| | - Luis F Durán-Armenta
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Agnes Tantos
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Rita Pancsa
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Ludo Van Den Bosch
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium
| | - Dominique Maes
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Peter Tompa
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium. .,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium. .,Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.
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23
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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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24
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Hentschel L, Hansen J, Egelhaaf SU, Platten F. The crystallization enthalpy and entropy of protein solutions: microcalorimetry, van't Hoff determination and linearized Poisson–Boltzmann model of tetragonal lysozyme crystals. Phys Chem Chem Phys 2021; 23:2686-2696. [DOI: 10.1039/d0cp06113a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Microcalorimetric and van't Hoff determinations as well as a theoretical description provide a consistent picture of the crystallization enthalpy and entropy of protein solutions and their dependence on physicochemical solution parameters.
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Affiliation(s)
- Lorena Hentschel
- Condensed Matter Physics Laboratory
- Heinrich Heine University
- 40225 Düsseldorf
- Germany
| | - Jan Hansen
- Condensed Matter Physics Laboratory
- Heinrich Heine University
- 40225 Düsseldorf
- Germany
| | - Stefan U. Egelhaaf
- Condensed Matter Physics Laboratory
- Heinrich Heine University
- 40225 Düsseldorf
- Germany
| | - Florian Platten
- Condensed Matter Physics Laboratory
- Heinrich Heine University
- 40225 Düsseldorf
- Germany
- Institute of Biological Information Processing (IBI-4: Biomacromolecular Systems and Processes)
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25
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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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26
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Dutra G, Komuczki D, Jungbauer A, Satzer P. Continuous capture of recombinant antibodies by ZnCl 2 precipitation without polyethylene glycol. Eng Life Sci 2020; 20:265-274. [PMID: 32647505 PMCID: PMC7336134 DOI: 10.1002/elsc.201900160] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/18/2020] [Accepted: 03/05/2020] [Indexed: 12/29/2022] Open
Abstract
The capture of recombinant antibodies from cell culture broth is the first critical step of downstream processing. We were able to develop a precipitation-based method for the capture and purification of monoclonal antibodies based on divalent cations, namely ZnCl2. Traditional precipitation processes have to deal with high dilution factors especially for resolubilization and higher viscosity due to the use of PEG as precipitation or co-precipitation agent. By the use of the crosslinking nature of divalent cations without the use of PEG, we kept viscosity from the supernatant and resolubilization dilution factors very low. This is especially beneficial for the solid-liquid separation for the harvest and wash of the precipitate in continuous mode. For this harvest and wash, we used tangential flow filtration that benefits a lot from low viscosity solutions, which minimizes the membrane fouling. With this precipitation based on ZnCl2, we were able to implement a very lean and efficient process. We demonstrated precipitation studies with three different antibodies, Adalimumab, Trastuzumab, and Denosumab, and a continuous capture case study using tangential flow filtration for precipitate recovery. In this study, we achieved yields of 70%.
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Affiliation(s)
- Gregory Dutra
- Department of BiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Daniel Komuczki
- Department of BiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Alois Jungbauer
- Department of BiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
- Austrian Centre of Industrial Biotechnology (ACIB)ViennaAustria
| | - Peter Satzer
- Department of BiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
- Austrian Centre of Industrial Biotechnology (ACIB)ViennaAustria
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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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28
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Narayanan T, Konovalov O. Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E752. [PMID: 32041363 PMCID: PMC7040635 DOI: 10.3390/ma13030752] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/17/2022]
Abstract
This article aims to provide an overview of broad range of applications of synchrotron scattering methods in the investigation of nanoscale materials. These scattering techniques allow the elucidation of the structure and dynamics of nanomaterials from sub-nm to micron size scales and down to sub-millisecond time ranges both in bulk and at interfaces. A major advantage of scattering methods is that they provide the ensemble averaged information under in situ and operando conditions. As a result, they are complementary to various imaging techniques which reveal more local information. Scattering methods are particularly suitable for probing buried structures that are difficult to image. Although, many qualitative features can be directly extracted from scattering data, derivation of detailed structural and dynamical information requires quantitative modeling. The fourth-generation synchrotron sources open new possibilities for investigating these complex systems by exploiting the enhanced brightness and coherence properties of X-rays.
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29
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Falke S, Brognaro H, Martirosyan A, Dierks K, Betzel C. A multi-channel in situ light scattering instrument utilized for monitoring protein aggregation and liquid dense cluster formation. Heliyon 2019; 5:e03016. [PMID: 31886430 PMCID: PMC6921120 DOI: 10.1016/j.heliyon.2019.e03016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/29/2019] [Accepted: 12/06/2019] [Indexed: 12/18/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) phenomena have been observed in vitro as well as in vivo and came in focus of interdisciplinary research activities particularly aiming at understanding the physico-chemical pathways of LLPS and its functionality in recent years. Dynamic light scattering (DLS) has been proven to be a most efficient method to analyze macromolecular clustering in solutions and suspensions with diverse applications in life sciences, material science and biotechnology. For spatially and time-resolved investigations of LLPS, i.e. formation of liquid dense protein clusters (LDCs) and aggregation, a novel eight-channel in situ DLS instrument was designed, constructed and applied. The real time formation of LDCs of glucose isomerase (GI) and bovine pancreatic trypsin inhibitor (BPTI) under different physico-chemical conditions was investigated in situ. Complex shifts in the particle size distributions indicated growth of LDCs up to the μm size regime. Additionally, near-UV circular dichroism spectroscopy was performed to monitor the folding state of the proteins in the process of LDC formation.
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Affiliation(s)
- Sven Falke
- University Hamburg, Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, c/o DESY, Build. 22a, Notkestr. 85, 22607, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, c/o DESY, Luruper Chaussee 149, Hamburg, 22607, Germany
| | - Hévila Brognaro
- University Hamburg, Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, c/o DESY, Build. 22a, Notkestr. 85, 22607, Hamburg, Germany
- Centre for Free-Electron-Laser Science, c/o DESY, Luruper Chaussee 149, Hamburg, 22607, Germany
| | - Arayik Martirosyan
- University Hamburg, Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, c/o DESY, Build. 22a, Notkestr. 85, 22607, Hamburg, Germany
| | - Karsten Dierks
- Xtal Concepts GmbH, Schnackenburgallee 13, 22525, Hamburg, Germany
| | - Christian Betzel
- University Hamburg, Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, c/o DESY, Build. 22a, Notkestr. 85, 22607, Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, c/o DESY, Luruper Chaussee 149, Hamburg, 22607, Germany
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30
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Cinar S, Cinar H, Chan HS, Winter R. Pressure-Sensitive and Osmolyte-Modulated Liquid–Liquid Phase Separation of Eye-Lens γ-Crystallins. J Am Chem Soc 2019; 141:7347-7354. [DOI: 10.1021/jacs.8b13636] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Süleyman Cinar
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Hasan Cinar
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Hue Sun Chan
- Departments of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Roland Winter
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
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31
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Matsarskaia O, Da Vela S, Mariani A, Fu Z, Zhang F, Schreiber F. Phase-Separation Kinetics in Protein-Salt Mixtures with Compositionally Tuned Interactions. J Phys Chem B 2019; 123:1913-1919. [PMID: 30702291 DOI: 10.1021/acs.jpcb.8b10725] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Liquid-liquid phase separation (LLPS) in protein systems is relevant for many phenomena, from protein condensation diseases to subcellular organization to possible pathways toward protein crystallization. Understanding and controlling LLPS in proteins is therefore highly relevant for various areas of (biological) soft matter research. Solutions of the protein bovine serum albumin (BSA) have been shown to have a lower critical solution temperature-LLPS (LCST-LLPS) induceable by multivalent salts. Importantly, the nature of the multivalent cation used influences the LCST-LLPS in such systems. Here, we present a systematic ultrasmall-angle X-ray scattering investigation of the kinetics of LCST-LLPS of BSA in the presence of different mixtures of HoCl3 and LaCl3, resulting in different effective interprotein attraction strengths. We monitor the characteristic length scales ξ( t, Tfin) after inducing LLPS by subjecting the respective systems to temperature jumps in their liquid-liquid coexistence regions. With increasing interprotein attraction and increasing Tfin, we observe an increasing deviation from the growth law of ξ ∼ t1/3 and an increased trend toward arrest. We thus establish a multidimensional method to tune phase transitions in our systems. Our findings help shed light on general questions regarding LLPS and the tunability of its kinetics in both proteins and colloidal systems.
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Affiliation(s)
- Olga Matsarskaia
- Institut für Angewandte Physik , Universität Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Stefano Da Vela
- Institut für Angewandte Physik , Universität Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Alessandro Mariani
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38043 Grenoble Cedex 9 , France
| | - Zhendong Fu
- Forschungszentrum Jülich GmbH, JCNS@MLZ , Lichtenbergstrasse 1 , 85747 Garching , 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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32
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Braun MK, Sauter A, Matsarskaia O, Wolf M, Roosen-Runge F, Sztucki M, Roth R, Zhang F, Schreiber F. Reentrant Phase Behavior in Protein Solutions Induced by Multivalent Salts: Strong Effect of Anions Cl - Versus NO 3.. J Phys Chem B 2018; 122:11978-11985. [PMID: 30461282 DOI: 10.1021/acs.jpcb.8b10268] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this work, the effects of the two anions Cl- and NO3- on the phase behavior of bovine serum albumin (BSA) in solution with trivalent salts are compared systematically. In the presence of trivalent metal salts, negatively charged proteins such as BSA in solution undergo a reentrant condensation (RC) phase behavior, which has been established for several proteins with chlorides of trivalent salts. Here, we show that replacing Cl- by NO3- leads to a marked change in the phase behavior. The effect is investigated for the two different cations Y3+ and La3+. The salts are thus YCl3, Y(NO3)3, LaCl3, and La(NO3)3. The experimental phase behavior shows that while the chloride salts induce both liquid-liquid phase separation (LLPS) and RC, the nitrate salts also induce LLPS, but RC becomes partial with La(NO3)3 and disappears with Y(NO3)3. The observed phase behavior is rationalized by effective protein-protein interactions which are characterized using small-angle X-ray scattering. The results based on the reduced second virial coefficients B2/ B2HS and 1/ I( q → 0) demonstrate that the NO3- salts induce a stronger attraction than the Cl- salts. Overall, the effective attraction, the width of the condensed regime in the RC phase diagram, and the nature of LLPS follow the order LaCl3 < YCl3 < La(NO3)3 < Y(NO3)3. Despite the decisive role of cations in RC phase behavior, isothermal titration calorimetry measurements indicate that replacing anions does not significantly influence the cation binding to proteins. The experimental results observed are discussed based on an "enhanced Hofmeister effect" including electrostatic and hydrophobic interactions between protein-cation complexes.
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Affiliation(s)
- Michal K Braun
- Institut für Angewandte Physik , Universität Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Andrea Sauter
- Institut für Angewandte Physik , Universität Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Olga Matsarskaia
- Institut für Angewandte Physik , Universität Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Marcell Wolf
- Institut für Angewandte Physik , Universität Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Felix Roosen-Runge
- Division of Physical Chemistry, Department of Chemistry , Lund University , Naturvetarvägen 14 , 22100 Lund , Sweden
| | - Michael Sztucki
- ESRF-The European Synchrotron Radiation Facility , 71 avenue des Martyrs , 38000 Grenoble , France
| | - Roland Roth
- Institut für Theoretische Physik , Universität Tübingen , Auf der Morgenstelle 14 , 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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