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Islam M, Shen F, Regmi D, Petersen K, Karim MRU, Du D. Tau liquid-liquid phase separation: At the crossroads of tau physiology and tauopathy. J Cell Physiol 2024; 239:e30853. [PMID: 35980344 PMCID: PMC9938090 DOI: 10.1002/jcp.30853] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/12/2022] [Accepted: 07/22/2022] [Indexed: 12/14/2022]
Abstract
Abnormal deposition of tau in neurons is a hallmark of Alzheimer's disease and several other neurodegenerative disorders. In the past decades, extensive efforts have been made to explore the mechanistic pathways underlying the development of tauopathies. Recently, the discovery of tau droplet formation by liquid-liquid phase separation (LLPS) has received a great deal of attention. It has been reported that tau condensates have a biological role in promoting and stabilizing microtubule (MT) assembly. Furthermore, it has been hypothesized that the transition of phase-separated tau droplets to a gel-like state and then to fibrils is associated with the pathology of neurodegenerative diseases. In this review, we outline LLPS, the structural disorder that facilitates tau droplet formation, the effects of posttranslational modification of tau on condensate formation, the physiological function of tau droplets, the pathways from droplet to toxic fibrils, and the therapeutic strategies for tauopathies that might evolve from toxic droplets. We expect a deeper understanding of tau LLPS will provide additional insights into tau physiology and tauopathies.
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Affiliation(s)
- Majedul Islam
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Fengyun Shen
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Deepika Regmi
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Katherine Petersen
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Md Raza Ul Karim
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Deguo Du
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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2
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Ma Y, Heil C, Nagy G, Heller WT, An Y, Jayaraman A, Bharti B. Synergistic Role of Temperature and Salinity in Aggregation of Nonionic Surfactant-Coated Silica Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5917-5928. [PMID: 37053432 PMCID: PMC10134496 DOI: 10.1021/acs.langmuir.3c00432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/03/2023] [Indexed: 06/19/2023]
Abstract
The adsorption of nonionic surfactants onto hydrophilic nanoparticles (NPs) is anticipated to increase their stability in aqueous medium. While nonionic surfactants show salinity- and temperature-dependent bulk phase behavior in water, the effects of these two solvent parameters on surfactant adsorption and self-assembly onto NPs are poorly understood. In this study, we combine adsorption isotherms, dispersion transmittance, and small-angle neutron scattering (SANS) to investigate the effects of salinity and temperature on the adsorption of pentaethylene glycol monododecyl ether (C12E5) surfactant on silica NPs. We find an increase in the amount of surfactant adsorbed onto the NPs with increasing temperature and salinity. Based on SANS measurements and corresponding analysis using computational reverse-engineering analysis of scattering experiments (CREASE), we show that the increase in salinity and temperature results in the aggregation of silica NPs. We further demonstrate the non-monotonic changes in viscosity for the C12E5-silica NP mixture with increasing temperature and salinity and correlate the observations to the aggregated state of NPs. The study provides a fundamental understanding of the configuration and phase transition of the surfactant-coated NPs and presents a strategy to manipulate the viscosity of such dispersion using temperature as a stimulus.
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Affiliation(s)
- Yingzhen Ma
- Cain
Department of Chemical Engineering, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
| | - Christian Heil
- Department
of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Gergely Nagy
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37831, United States
| | - William T. Heller
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yaxin An
- Cain
Department of Chemical Engineering, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
| | - Arthi Jayaraman
- Department
of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Bhuvnesh Bharti
- Cain
Department of Chemical Engineering, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
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3
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Lamberti G, Domenichelli V, Straziuso S, Pelusi G, Natile M, Ancora G, Barone G. Use of the Dialkylcarbamoylchloride Dressing in the Care of Central Venous Access Exit Site in a Pediatric and Neonatal Population. Diagnostics (Basel) 2023; 13:diagnostics13091520. [PMID: 37174912 PMCID: PMC10177172 DOI: 10.3390/diagnostics13091520] [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: 03/28/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
Dialkylcarbamoylchloride dressing is a fatty acid derivative that has been shown in vitro to bind a number of pathogenic microorganisms. The purpose of this prospective study was to evaluate the safety and the efficacy of this technology in the care of the exit site of central venous catheter in a paediatric and neonatal population. METHODS The study was conducted from September 2020 to December 2022 at the Infermi Hospital in Rimini. Central venous catheters were placed using the SIC bundle for insertion. Dialkylcarbamoylchloride dressing was placed below the subcutaneous anchoring at the time of CVC placement and at each dressing change. Data about the catheters and the exit site were recorded and then compared with an historical cohort. RESULTS 118 catheters were placed during the studied period. The dialkylcarbamoylchloride dressing was well-tolerated. No case of systemic or local infection was recorded. The comparison with the historical cohort showed a reduction in the rate of exit site infection (p value 0.03). CONCLUSION Dialkylcarbamoylchloride dressing is well-tolerated in paediatric and neonatal population. It represents a promising tool as a strategy for infection prevention.
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Affiliation(s)
- Giorgio Lamberti
- Pediatric Surgery, Infermi Hospital, AUSL della Romagna, 47923 Rimini, Italy
| | | | - Simona Straziuso
- Pediatric Surgery, Infermi Hospital, AUSL della Romagna, 47923 Rimini, Italy
| | - Gabriella Pelusi
- Pediatric Surgery, Infermi Hospital, AUSL della Romagna, 47923 Rimini, Italy
| | - Miria Natile
- Neonatal Intensive Care Unit, Infermi Hospital, AUSL della Romagna, 47923 Rimini, Italy
| | - Gina Ancora
- Neonatal Intensive Care Unit, Infermi Hospital, AUSL della Romagna, 47923 Rimini, Italy
| | - Giovanni Barone
- Neonatal Intensive Care Unit, Infermi Hospital, AUSL della Romagna, 47923 Rimini, Italy
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4
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Asadzadeh B, Majdan-Cegincara R, Zafarani-Moattar MT. Study of Thermodynamic Properties of l-Serine and l-Threonine in Aqueous Solutions of 1-(2-Carboxyethyl)-3-methylimidazolium Chloride [HOOCEMIM][Cl]. J SOLUTION CHEM 2023. [DOI: 10.1007/s10953-022-01235-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AbstractThe stability of amino acids in solutions containing electrolytes and the effect of ambient pH on their biological activity is an important research area. In this research work, the volumetric and transport properties of ionic liquid (IL) aqueous solution with special performance of 1-(2-carboxyethyl)-3-methylimidazolium chloride ([HOOCEMIM][Cl]) were studied. The selected IL acts as an electrolyte and allows the study of systems containing amino acids at acidic pH. In this work, the density, speed of sound and viscosity of binary and ternary solutions of IL in aqueous solution of amino acids in the structure of proteins, namely l-serine and l-threonine within IL molality range of (0.05, 0.07 and 0.09 mol·kg−1) were measured at 298.15 K. From these quantities, apparent molar volume, limiting apparent molar volume, apparent molar isentropic compression, limiting apparent molar isentropic compression, transfer standard volumes for amino acids from water to the aqueous IL solutions and viscosity B-coefficients were calculated using the equations of Redlich–Meyer and Jones–Dole. Close examination of literature indicates that there is no data for water activity for solution of l-serine + H2O at 308.15 and 318.15 K. In this way water activity, osmotic coefficient and vapor pressure were measured and using the interaction parameters of Wilson, NRTL, NRF-NRTL and UNIQUAC models, activity coefficient values of l-serine calculated.
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5
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Lin Y, Fichou Y, Longhini AP, Llanes LC, Yin P, Bazan GC, Kosik KS, Han S. Liquid-Liquid Phase Separation of Tau Driven by Hydrophobic Interaction Facilitates Fibrillization of Tau. J Mol Biol 2021; 433:166731. [PMID: 33279579 PMCID: PMC7855949 DOI: 10.1016/j.jmb.2020.166731] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/29/2020] [Accepted: 11/30/2020] [Indexed: 11/17/2022]
Abstract
Amyloid aggregation of tau protein is implicated in neurodegenerative diseases, yet its facilitating factors are poorly understood. Recently, tau has been shown to undergo liquid liquid phase separation (LLPS) both in vivo and in vitro. LLPS was shown to facilitate tau amyloid aggregation in certain cases, while being independent of aggregation in other cases. It is therefore important to understand the differentiating properties that resolve this apparent conflict. We report on a model system of hydrophobically driven LLPS induced by high salt concentration (LLPS-HS), and compare it to electrostatically driven LLPS represented by tau-RNA/heparin complex coacervation (LLPS-ED). We show that LLPS-HS promotes tau protein dehydration, undergoes maturation and directly leads to canonical tau fibrils, while LLPS-ED is reversible, remains hydrated and does not promote amyloid aggregation. We show that the nature of the interaction driving tau condensation is a differentiating factor between aggregation-prone and aggregation-independent LLPS.
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Affiliation(s)
- Yanxian Lin
- Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106, United States
| | - Yann Fichou
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States
| | - Andrew P Longhini
- Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA 93106, United States
| | - Luana C Llanes
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States; Center for Polymers and Organic Solids, University of California, Santa Barbara, CA 93106, United States
| | - Pengyi Yin
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States
| | - Guillermo C Bazan
- Departments of Chemistry and Chemical Engineering, National University of Singapore, 117543, Singapore
| | - Kenneth S Kosik
- Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA 93106, United States; Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States; Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, United States.
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6
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Morilla‐Herrera JC, Morales‐Asencio JM, Gómez‐González AJ, Díez‐De Los Ríos A, Lupiáñez‐Pérez I, Acosta‐Andrade C, Aranda‐Gallardo M, Moya‐Suárez AB, Kaknani‐Uttumchandani S, García‐Mayor S. Effectiveness of a hydrophobic dressing for microorganisms' colonization of vascular ulcers: Protocol for a randomized controlled trial (CUCO-UV Study). J Adv Nurs 2020; 76:2191-2197. [PMID: 32395842 PMCID: PMC7496185 DOI: 10.1111/jan.14412] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/09/2020] [Accepted: 04/28/2020] [Indexed: 01/08/2023]
Abstract
AIM To determine the effectiveness of a hydrophobic dressing (Cutimed Sorbact® ) against a silver dressing (Aquacel® Ag Extra) in the level of colonization of chronic venous leg ulcers. The secondary endpoints are health-related quality of life, level of pain, and time to complete healing. DESIGN Open randomized controlled trial, with blinded endpoint. METHODS Patients with chronic venous leg ulcers with signs of critical colonization will be randomized in a concealed sequence using computer software to receive one of the alternative dressings. A total of 204 participants recruited in Primary Health Care and nursing homes will be necessary to assure statistical power. Measures will include sociodemographic variables, wound-related variables (area, exudate, and time to healing), level of pain, adverse effects, and health-related quality of life. Smear samples will be collected from the ulcers and will be subject to DNA-typing technique through polymerase chain reaction to obtain the level of colony-forming units. Measures will be collected at baseline, 4, 8, and 12 weeks. DISCUSSION Elevated levels of microorganisms prevent wound healing and favour its chronification. The main target when colonization is present is to reduce the bacterial load to levels that promote immune system mobilization. Hydrophobic dressings prevent the formation of biofilm in the wound by means of physical effect, so that the possibility of antimicrobial resistance is significantly reduced. IMPACT Current evidence about the effectiveness of dressings to minimize venous leg ulcers colonization is very limited. Previous studies have important methodological flaws. This study will permit to obtain the effectiveness of hydrophobic dressings against silver dressings with a robust design based on conditions of routine clinical practice in Primary Health Care and nursing homes.
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Affiliation(s)
- Juan C. Morilla‐Herrera
- Department of NursingUniversity of Málaga, Faculty of Health SciencesMalagaSpain
- Distrito Sanitario Málaga – Valle del GuadalhorceMalagaSpain
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
| | - José M. Morales‐Asencio
- Department of NursingUniversity of Málaga, Faculty of Health SciencesMalagaSpain
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
| | | | | | - Inmaculada Lupiáñez‐Pérez
- Department of NursingUniversity of Málaga, Faculty of Health SciencesMalagaSpain
- Distrito Sanitario Málaga – Valle del GuadalhorceMalagaSpain
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
| | | | - Marta Aranda‐Gallardo
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
- Agencia Sanitaria Costa del SolMarbellaSpain
| | - Ana B. Moya‐Suárez
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
- Agencia Sanitaria Costa del SolMarbellaSpain
| | - Shakira Kaknani‐Uttumchandani
- Department of NursingUniversity of Málaga, Faculty of Health SciencesMalagaSpain
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
| | - Silvia García‐Mayor
- Department of NursingUniversity of Málaga, Faculty of Health SciencesMalagaSpain
- Instituto de Investigación Biomédica de Málaga (IBIMA)MalagaSpain
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7
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Zafari M, Aghajani S, Mansouri Boroujeni M, Nosrati H. Vancomycin-loaded electrospun polycaprolactone/nano-hydroxyapatite membrane for the treatment of blood infections. Med Hypotheses 2020; 144:109992. [PMID: 32563972 DOI: 10.1016/j.mehy.2020.109992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 05/31/2020] [Accepted: 06/10/2020] [Indexed: 12/25/2022]
Abstract
Nowadays, because of the resistance of bacteria to antibiotics, researchers are trying to make new antibiotics or sometimes even bring them back into the treatment cycle so that they could eliminate the bacteria's resistance. On the other hand, the use of nanofibers has become widespread in many fields for their unique properties and convenient design. The present study focuses on the production of hydrophobic nanofibers to absorb the bacteria and their toxins from the bloodstream that contains the infection. Many bacterial surfaces have hydrophobic surfactant properties due to hydrophobic surface protein. According to the principle of binding two hydrophobic molecules to each other in an aqueous medium, the nanofibers are designed to physically absorb the bacteria. The use of antibiotics in the study can remove some unattached bacteria. In addition, using nanofiber manufacturing techniques can reduce the resistance of bacteria to antibiotics. The construction of the desired membrane can be used in subsequent studies as a replacement membrane for dialysis filters.
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Affiliation(s)
- Mahdi Zafari
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Sajad Aghajani
- Cellular and Molecular Research Center, Basic Health Science Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Milad Mansouri Boroujeni
- Cellular and Molecular Research Center, Basic Health Science Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Hamed Nosrati
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, Iran.
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8
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Breidert M, Eftekhari P, Louis F, Rotoiu C, Rath T, Neurath MF, Atreya R. Functional Molecular Network Analysis Enables Prediction of Response to Vedolizumab Therapy in Anti-TNF Refractory IBD Patients. CROHNS & COLITIS 360 2020; 2:otaa037. [PMID: 32776006 PMCID: PMC7397736 DOI: 10.1093/crocol/otaa037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Indexed: 02/07/2023]
Abstract
Background We applied for the first time 2 label-free technologies, physiological intermolecular modulation spectroscopy (PIMS) and nematic protein organization technic (NPOT) in anti-tumor necrosis factor (TNF) refractory inflammatory bowel disease (IBD) patients to identify clinical responders to vedolizumab therapy and elucidate their underlying functional molecular network. Methods PIMS analysis was performed in peripheral blood taken prior to the first vedolizumab application in 20 IBD patients (Crohn disease n = 13; ulcerative colitis n = 7) refractory to at least 1 previous anti-TNF agent therapy. Peripheral blood taken from clinical responders and nonresponders at week 14 of vedolizumab therapy were additionally subjected to NPOT analysis. Response to therapy was assessed by respective clinical disease activity scores (partial Mayo Score and Harvey-Bradshaw Index). Results Clinical response to vedolizumab treatment was observed in 7 of 13 Crohn disease and 4 of 7 ulcerative colitis patients at week 14. Response to therapy was accurately predicted by PIMS blood analysis in 100% of ulcerative colitis and 77% of Crohn disease patients. Overall prediction of clinical response with PIMS blood analysis was achieved with a 89% positive predictive value and a 82% negative predictive value. NPOT analysis revealed the heightened expression of the proteins ITGB7, ITGAV, ITG3, PF4, and ASGH in the peripheral blood of vedolizumab responders compared to nonresponders. Conclusions PIMS analysis of the blood of anti-TNF refractory IBD patients was able to stratify responders to vedolizumab therapy with high accuracy and specificity. NPOT technology could decipher underling molecular networks in the blood of responders, enabling subsequent personalized therapeutic approaches in IBD.
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Affiliation(s)
- Matthias Breidert
- Department of Gastroenterology and Hepatology, City Hospital Waid and Triemli, Zürich, Switzerland
| | | | - François Louis
- Inoviem Scientific, BIOPARC 3, Illkirch-Graffenstaden, France
| | - Claudia Rotoiu
- Department of Gastroenterology and Hepatology, City Hospital Waid and Triemli, Zürich, Switzerland
| | - Timo Rath
- Department of Medicine I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Deutsches Zentrum Immuntherapie (DZI), Friedrich-Alexander-Universität, Erlangen-Nürnberg, Erlangen, Germany
| | - Markus F Neurath
- Department of Medicine I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Deutsches Zentrum Immuntherapie (DZI), Friedrich-Alexander-Universität, Erlangen-Nürnberg, Erlangen, Germany
| | - Raja Atreya
- Department of Medicine I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Deutsches Zentrum Immuntherapie (DZI), Friedrich-Alexander-Universität, Erlangen-Nürnberg, Erlangen, Germany.,The Transregio 241 IBDome Consortium
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9
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Qin S, Zhou HX. Calculation of Second Virial Coefficients of Atomistic Proteins Using Fast Fourier Transform. J Phys Chem B 2019; 123:8203-8215. [PMID: 31490691 DOI: 10.1021/acs.jpcb.9b06808] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The second virial coefficient, B2, measures a protein solution's deviation from ideal behavior. It is widely used to predict or explain solubility, crystallization condition, aggregation propensity, and critical temperature for liquid-liquid phase separation. B2 is determined by the interaction energy between two protein molecules and, specifically, by the integration of the Mayer f-function in the relative configurational space (translation and rotation) of the two molecules. Simple theoretical models, such as one attributed to Derjaguin, Landau, Verwey, and Overbeek (DLVO), can fit the dependence of B2 on salt concentrations. However, model parameters derived often are physically unrealistic and hardly transferable from protein to protein. Previous B2 calculations incorporating atomistic details were done with limited sampling in the configurational space, due to enormous computational cost. Our FMAP method, based on fast Fourier transform, can considerably accelerate such calculations, and here we adapt it to calculate B2 values for proteins represented at the atomic level in implicit solvent. After tuning of a single parameter in the energy function, FMAPB2 predicts well the B2 values for lysozyme and other proteins over wide ranges of solvent conditions (salt concentration, pH, and temperature). The method is available as a web server at http://pipe.rcc.fsu.edu/fmapb2 .
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Affiliation(s)
- Sanbo Qin
- Department of Chemistry and Department of Physics , University of Illinois at Chicago , Chicago , Illinois 60607 , United States.,Institute of Molecular Biophysics , Florida State University , Tallahassee , Florida 32306 , United States
| | - Huan-Xiang Zhou
- Department of Chemistry and Department of Physics , University of Illinois at Chicago , Chicago , Illinois 60607 , United States
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10
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Liu Y, Xi Y. Colloidal systems with a short-range attraction and long-range repulsion: Phase diagrams, structures, and dynamics. Curr Opin Colloid Interface Sci 2019; 39. [PMID: 34140838 DOI: 10.1016/j.cocis.2019.01.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Colloidal systems with both a short-range attraction and long-range repulsion (SALR) have rich phases compared with the traditional hard sphere systems or sticky hard sphere systems. The competition between the short-range attraction and long-range repulsion results in the frustrated phase separation, which leads to the formation of intermediate range order (IRO) structures and introduces new phases to both equilibrium and nonequilibrium phase diagrams, such as clustered fluid, cluster percolated fluid, Wigner glass, and cluster glass. One hallmark feature of many SALR systems is the appearance of the IRO peak in the interparticle structure factor, which is associated with different types of IRO structures. The relationship between the IRO peak and the clustered fluid state has been careful investigated. Not surprisingly, the morphology of clusters in solutions can be affected and controlled by the SALR potential. And the effect of the SALR potential on the dynamic properties is also reviewed here. Even though much progress has been made in understanding SALR systems, many future works are still needed to have quantitative comparisons between experiments and simulations/theories and understand the differences from different experimental systems. Owing to the large parameter space available for SALR systems, many exciting features of SALR systems are not fully explored yet. Because proteins in low-salinity solutions have SALR interactions, the understanding of SALR systems can greatly help understand protein behavior in concentrated solutions or crowded conditions.
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Affiliation(s)
- Yun Liu
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.,Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, DE, 19716, USA.,Department of Physics & Astronomy, University of Delaware, Newark, DE, 19716, USA
| | - Yuyin Xi
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.,Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, DE, 19716, USA
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11
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Tatini D, Sarri F, Maltoni P, Ambrosi M, Carretti E, Ninham BW, Lo Nostro P. Specific ion effects in polysaccharide dispersions. Carbohydr Polym 2017; 173:344-352. [DOI: 10.1016/j.carbpol.2017.05.078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/22/2017] [Accepted: 05/24/2017] [Indexed: 11/15/2022]
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12
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Bauer KC, Hämmerling F, Kittelmann J, Dürr C, Görlich F, Hubbuch J. Influence of structure properties on protein-protein interactions-QSAR modeling of changes in diffusion coefficients. Biotechnol Bioeng 2017; 114:821-831. [PMID: 27801503 DOI: 10.1002/bit.26210] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 10/05/2016] [Accepted: 10/28/2016] [Indexed: 11/07/2022]
Abstract
Information about protein-protein interactions provides valuable knowledge about the phase behavior of protein solutions during the biopharmaceutical production process. Up to date it is possible to capture their overall impact by an experimentally determined potential of mean force. For the description of this potential, the second virial coefficient B22, the diffusion interaction parameter kD, the storage modulus G', or the diffusion coefficient D is applied. In silico methods do not only have the potential to predict these parameters, but also to provide deeper understanding of the molecular origin of the protein-protein interactions by correlating the data to the protein's three-dimensional structure. This methodology furthermore allows a lower sample consumption and less experimental effort. Of all in silico methods, QSAR modeling, which correlates the properties of the molecule's structure with the experimental behavior, seems to be particularly suitable for this purpose. To verify this, the study reported here dealt with the determination of a QSAR model for the diffusion coefficient of proteins. This model consisted of diffusion coefficients for six different model proteins at various pH values and NaCl concentrations. The generated QSAR model showed a good correlation between experimental and predicted data with a coefficient of determination R2 = 0.9 and a good predictability for an external test set with R2 = 0.91. The information about the properties affecting protein-protein interactions present in solution was in agreement with experiment and theory. Furthermore, the model was able to give a more detailed picture of the protein properties influencing the diffusion coefficient and the acting protein-protein interactions. Biotechnol. Bioeng. 2017;114: 821-831. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Katharina Christin Bauer
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany
| | - Frank Hämmerling
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany
| | - Jörg Kittelmann
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany
| | - Cathrin Dürr
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany
| | - Fabian Görlich
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany
| | - Jürgen Hubbuch
- Institute of Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany
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13
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Medda L, Monduzzi M, Salis A. The molecular motion of bovine serum albumin under physiological conditions is ion specific. Chem Commun (Camb) 2015; 51:6663-6. [DOI: 10.1039/c5cc01538c] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Specific ion effects on the Brownian motion of BSA protein under physiological conditions give new useful insights into the electrolyte–protein interactions and the molecular mechanisms involved in the Hofmeister effect.
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Affiliation(s)
- Luca Medda
- Department of Chemical and Geological Sciences
- University of Cagliari-CSGI and CNBS
- Cittadella Universitaria
- 09042- Monserrato (CA)
- Italy
| | - Maura Monduzzi
- Department of Chemical and Geological Sciences
- University of Cagliari-CSGI and CNBS
- Cittadella Universitaria
- 09042- Monserrato (CA)
- Italy
| | - Andrea Salis
- Department of Chemical and Geological Sciences
- University of Cagliari-CSGI and CNBS
- Cittadella Universitaria
- 09042- Monserrato (CA)
- Italy
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14
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Salt-induced protein precipitation in aqueous solution: Single and binary protein systems. Macromol Res 2013. [DOI: 10.1007/bf03218278] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Franco LFM, Pessôa Filho PDA. On the relationship between the solubility of proteins and the osmotic second virial coefficient. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2013. [DOI: 10.1590/s0104-66322013000100011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Second Osmotic Virial Coefficients and Aggregation of Monoclonal Antibodies by Static Laser Light Scattering. Z PHYS CHEM 2013. [DOI: 10.1524/zpch.2013.0325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The second osmotic virial coefficient and the apparent molar mass of two human and one mouse monoclonal antibodies were measured in different aequeous buffer solutions which also contained sodium chloride or ammonium sulfate, respectively, by static laser light scattering in batch mode. The apparent molar mass indicates aggregation. At a constant pH value of 6.5 the sodium chloride concentration was varied from 0 to 2 M and the ammonium sulfate concentration from 0 to 0.8 M, respectively. A 20 mM sodium-phosphate buffer was used for all experiments. Furthermore the pH value was varied without adding additional salt from 4.5 to 10. The results of the salt dependency are in line with the Hofmeister-series. The results of the pH dependency correspond to the net charge of the molecules.
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17
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Raccosta S, Martorana V, Manno M. Thermodynamic versus conformational metastability in fibril-forming lysozyme solutions. J Phys Chem B 2012; 116:12078-87. [PMID: 22984801 DOI: 10.1021/jp303430g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of intermolecular interaction in fibril-forming protein solutions and its relation with molecular conformation is a crucial aspect for the control and inhibition of amyloid structures. Here, we study the fibril formation and the protein-protein interactions of lysozyme at acidic pH and low ionic strength. The amyloid formation occurs after a long lag time and is preceded by the formation of oligomers, which seems to be off-pathway with respect to fibrillation. By measuring the osmotic isothermal compressibility and the collective diffusion coefficient of lysozyme in solution, we observe that the monomeric solution is kept in a thermodynamically metastable state by strong electrostatic repulsion, even in denaturing conditions. The measured repulsive interaction between monomers is satisfactorily accounted for by classical polyelectrolyte theory. Further, we observe a slow conformational change involving both secondary and tertiary structure, which drives the proteins toward a more hydrophobic conformation. Denatured proteins are driven out of metastability through conformational substates, which are kinetically populated and experience a lower activation energy for fibril formation. Thus, our results highlight the role of electrostatic repulsion, which hinders the aggregation of partially denatured proteins and operates as a gatekeeper favoring the association of those monomers whose conformation is capable of forming amyloid structure.
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Affiliation(s)
- Samuele Raccosta
- Institute of Biophysics, National Research Council of Italy, via U. La Malfa 153, I-90146 Palermo, Italy
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18
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Gögelein C, Wagner D, Cardinaux F, Nägele G, Egelhaaf SU. Effect of glycerol and dimethyl sulfoxide on the phase behavior of lysozyme: theory and experiments. J Chem Phys 2012; 136:015102. [PMID: 22239802 DOI: 10.1063/1.3673442] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Salt, glycerol, and dimethyl sulfoxide (DMSO) are used to modify the properties of protein solutions. We experimentally determined the effect of these additives on the phase behavior of lysozyme solutions. Upon the addition of glycerol and DMSO, the fluid-solid transition and the gas-liquid coexistence curve (binodal) shift to lower temperatures and the gap between them increases. The experimentally observed trends are consistent with our theoretical predictions based on the thermodynamic perturbation theory and the Derjaguin-Landau-Verwey-Overbeek model for the lysozyme-lysozyme pair interactions. The values of the parameters describing the interactions, namely the refractive indices, dielectric constants, Hamaker constant and cut-off length, are extracted from literature or are experimentally determined by independent experiments, including static light scattering, to determine the second virial coefficient. We observe that both, glycerol and DMSO, render the potential more repulsive, while sodium chloride reduces the repulsion.
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Affiliation(s)
- Christoph Gögelein
- Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, 37077 Göttingen, Germany.
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19
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Abramo MC, Caccamo C, Costa D, Pellicane G, Ruberto R, Wanderlingh U. Effective interactions in lysozyme aqueous solutions: A small-angle neutron scattering and computer simulation study. J Chem Phys 2012; 136:035103. [DOI: 10.1063/1.3677186] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Salis A, Cugia F, Parsons DF, Ninham BW, Monduzzi M. Hofmeister series reversal for lysozyme by change in pH and salt concentration: insights from electrophoretic mobility measurements. Phys Chem Chem Phys 2012; 14:4343-6. [DOI: 10.1039/c2cp40150a] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Affiliation(s)
- Martyn Butcher
- University of Plymouth Honorary Tissue Viability Research Nurse, Northern Devon Healthcare Trust, UK
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22
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Llop-Tous I, Madurga S, Giralt E, Marzabal P, Torrent M, Ludevid MD. Relevant elements of a maize gamma-zein domain involved in protein body biogenesis. J Biol Chem 2010; 285:35633-44. [PMID: 20829359 PMCID: PMC2975188 DOI: 10.1074/jbc.m110.116285] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 09/08/2010] [Indexed: 11/06/2022] Open
Abstract
The N-terminal proline-rich domain of γ-zein (Zera) plays an important role in protein body (PB) formation not only in the original host (maize seeds) but in a broad spectrum of eukaryotic cells. However, the elements within the Zera sequence that are involved in the biogenesis of PBs have not been clearly identified. Here, we focused on amino acid sequence motifs that could be involved in Zera oligomerization, leading to PB-like structures in Nicotiana benthamiana leaves. By using fusions of Zera with fluorescent proteins, we found that the lack of the repeat region (PPPVHL)(8) of Zera resulted in the secretion of the fusion protein but that this repeat by itself did not form PBs. Although the repeat region containing eight units was the most efficient for Zera self-assembly, shorter repeats of 4-6 units still formed small multimers. Based on site-directed mutagenesis of Zera cysteine residues and analysis of multimer formation, we conclude that the two N-terminal Cys residues of Zera (Cys(7) and Cys(9)) are critical for oligomerization. Immunoelectron microscopy and confocal studies on PB development over time revealed that early, small, Zera-derived oligomers were sequestered in buds along the rough ER and that the mature size of the PBs could be attained by both cross-linking of preformed multimers and the incorporation of new chains of Zera fusions synthesized by active membrane-bound ribosomes. Based on these results and on the behavior of the Zera structure determined by molecular dynamics simulation studies, we propose a model of Zera-induced PB biogenesis.
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Affiliation(s)
- Immaculada Llop-Tous
- From the Centre de Recerca en Agrigenòmica, Consejo Superior de Investigaciones Científicas, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Sergio Madurga
- the Departament de Química Física and IQTCUB, Universidad de Barcelona, Martí Franquès 1, 08028 Barcelona, Spain
| | - Ernest Giralt
- the Institut de Recerca Biomèdica, Parc Científic de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain, and
| | | | - Margarita Torrent
- From the Centre de Recerca en Agrigenòmica, Consejo Superior de Investigaciones Científicas, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - M. Dolors Ludevid
- From the Centre de Recerca en Agrigenòmica, Consejo Superior de Investigaciones Científicas, Jordi Girona 18-26, 08034 Barcelona, Spain
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23
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Le Brun V, Friess W, Bassarab S, Garidel P. Correlation of protein-protein interactions as assessed by affinity chromatography with colloidal protein stability: A case study with lysozyme. Pharm Dev Technol 2010; 15:421-30. [DOI: 10.3109/10837450903262074] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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24
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Cho JH, Cho MH, Hwang H, Bhoo SH, Hahn TR. Improvement of plant protein solubilization and 2-DE gel resolution through optimization of the concentration of Tris in the solubilization buffer. Mol Cells 2010; 29:611-6. [PMID: 20496115 DOI: 10.1007/s10059-010-0076-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 03/02/2010] [Accepted: 03/03/2010] [Indexed: 10/19/2022] Open
Abstract
It is important to solubilize acetone-precipitated proteins before isoelectric focusing (IEF) to achieve high resolution 2-DE gels. To resolve the maximum possible number of plant protein spots, we developed an improved solubilization buffer for plant proteins. We demonstrated that the resolution of 2-DE gels increased dramatically as the concentration of Tris-base increased, with maximum solubilization obtained at 200 mM Tris-base (Ly200T). The Ly200T buffer was more effective than the commonly used solubilization buffer containing 40 mM Tris at solubilizing acetone-precipitated plant proteins. Use of the Ly200T buffer to solubilize proteins resulted in an increase in intensity of approximately 30% of plant protein spots in the larger-than-40 kDa region of the gel. The Ly200T buffer also improved the resolution of abundant and basic proteins. Thus, the Ly200T buffer can be used to achieve greater resolution of protein spots in plant proteomics research.
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Affiliation(s)
- Jin-Hwan Cho
- Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Suwon, 446-701, Korea
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25
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Lo Nostro P, Peruzzi N, Severi M, Ninham BW, Baglioni P. Asymmetric Partitioning of Anions in Lysozyme Dispersions. J Am Chem Soc 2010; 132:6571-7. [DOI: 10.1021/ja101603n] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Niccolò Peruzzi
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Mirko Severi
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Barry W. Ninham
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Piero Baglioni
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino, Florence, Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
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26
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Bengali AN, Tessier PM. Biospecific protein immobilization for rapid analysis of weak protein interactions using self-interaction nanoparticle spectroscopy. Biotechnol Bioeng 2009; 104:240-50. [DOI: 10.1002/bit.22392] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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27
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Choi SH, Bae YC. Salt-induced protein separation in an aqueous electrolyte solution. KOREAN J CHEM ENG 2009. [DOI: 10.1007/s11814-009-0211-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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28
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Deshpande KS, Ahamed T, ter Horst JH, Jansens PJ, van der Wielen LAM, Ottens M. The use of self-interaction chromatography in stable formulation and crystallization of proteins. Biotechnol J 2009; 4:1266-77. [DOI: 10.1002/biot.200800226] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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29
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Carrotta R, Manno M, Giordano FM, Longo A, Portale G, Martorana V, Biagio PLS. Protein stability modulated by a conformational effector: effects of trifluoroethanol on bovine serum albumin. Phys Chem Chem Phys 2009; 11:4007-18. [PMID: 19440630 DOI: 10.1039/b818687a] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The link between the thermodynamic properties of a solution and the conformational space explored by a protein is of fundamental importance to understand and control solubility, misfolding and aggregation processes. Here, we study the thermodynamic and conformational stability of a model protein, bovine serum albumin (BSA), by addition of trifluoroethanol (TFE), which is known to affect both the solvent properties and the protein structure. The solvent-mediated pair-wise interactions are investigated by static and dynamic light scattering, and by small angle X-ray scattering. The protein conformational details are studied by far- and near-UV circular dichroism (CD), and steady state fluorescence from tryptophan and from 1-anilino-8-naphthalene sulfonate (ANS). At low TFE concentrations, our results show that protein-protein interaction is dominated by steric repulsion accompanied by a consistent protein solvation. Minor local conformational changes also occur, but they do not affect the stability of BSA. At TFE concentrations above the threshold of 16% v/v, attractive interactions become prevalent, along with conformational changes related to a loosening of BSA tertiary structure. The onset of thermodynamic instability is triggered by the enhancement of hydrophobic attraction over repulsion, due to minor local changes of protein conformation and hydration. In the present context, TFE acts as a conformational effector, since it affects the intermolecular interaction and the activity of the proteins in solution through a direct mechanism.
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Affiliation(s)
- Rita Carrotta
- Institute of Biophysics at Palermo, Italian National Research Council, via U. La Malfa 153, I-90146, Palermo, Italy
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30
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Zhao G, Peng G, Li F, Shi Q, Sun Y. 5-Aminoindole, a new ligand for hydrophobic charge induction chromatography. J Chromatogr A 2008; 1211:90-8. [DOI: 10.1016/j.chroma.2008.09.108] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 09/16/2008] [Accepted: 09/29/2008] [Indexed: 10/21/2022]
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31
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Gögelein C, Nägele G, Tuinier R, Gibaud T, Stradner A, Schurtenberger P. A simple patchy colloid model for the phase behavior of lysozyme dispersions. J Chem Phys 2008; 129:085102. [DOI: 10.1063/1.2951987] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Cheng YC, Bianco CL, Sandler SI, Lenhoff AM. Salting-Out of Lysozyme and Ovalbumin from Mixtures: Predicting Precipitation Performance from Protein−Protein Interactions. Ind Eng Chem Res 2008. [DOI: 10.1021/ie071462p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu-Chia Cheng
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716
| | - Carolina L. Bianco
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716
| | - Stanley I. Sandler
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716
| | - Abraham M. Lenhoff
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716
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33
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Zou G, de Leeuw E, Lubkowski J, Lu W. Molecular determinants for the interaction of human neutrophil alpha defensin 1 with its propeptide. J Mol Biol 2008; 381:1281-91. [PMID: 18616948 DOI: 10.1016/j.jmb.2008.06.066] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 06/17/2008] [Accepted: 06/23/2008] [Indexed: 01/30/2023]
Abstract
Human neutrophil alpha-defensins (HNPs) are cationic antimicrobial peptides that are synthesized in vivo as inactive precursors (proHNPs). Activation requires proteolytic excision of their anionic N-terminal inhibitory pro peptide. The pro peptide of proHNP1 also interacts specifically with and inhibits the antimicrobial activity of HNP1 inter-molecularly. In the light of the opposite net charges segregated in proHNP1, functional inhibition of the C-terminal defensin domain by its propeptide is generally thought to be of electrostatic nature. Using a battery of analogs of the propeptide and of proHNP1, we identified residues in the propeptide region important for HNP1 binding and inhibition. Only three anionic residues in the propeptide, Glu(15), Asp(20) and Glu(23), were modestly important for interactions with HNP1. By contrast, the hydrophobic residues in the central part of the propeptide, and the conserved hydrophobic motif Val(24)Val(25)Val(26)Leu(28) in particular, were critical for HNP1 binding and inhibition. Neutralization of all negative charges in the propeptide only partially activated the bactericidal activity of proHNP1. Our data indicate that hydrophobic forces have a dominant role in mediating the interactions between HNP1 and its propeptide--a finding largely contrasting the commonly held view that the interactions are of an electrostatic nature.
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Affiliation(s)
- Guozhang Zou
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201, USA
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34
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Protein-protein interaction on lysozyme crystallization revealed by rotational diffusion analysis. Biophys J 2008; 94:4484-92. [PMID: 18310245 DOI: 10.1529/biophysj.107.111872] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Intermolecular interactions between protein molecules diffusing in various environments underlie many biological processes as well as control protein crystallization, which is a crucial step in x-ray protein structure determinations. Protein interactions were investigated through protein rotational diffusion analysis. First, it was confirmed that tetragonal lysozyme crystals containing fluorescein-tagged lysozyme were successfully formed with the same morphology as that of native protein. Using this nondisruptive fluorescent tracer system, we characterized the effects of sodium chloride and ammonium sulfate concentrations on lysozyme-lysozyme interactions by steady-state and time-resolved fluorescence anisotropy measurements and the introduction of a novel interaction parameter, k(rot). The results suggested that the specific attractive interaction, which was reflected in the retardation of the protein rotational diffusion, was induced depending on the salt type and its concentration. The change in the attractive interactions also correlated with the crystallization/precipitation behavior of lysozyme. Moreover, we discuss the validity of our rotational diffusion analysis through comparison with the osmotic second virial coefficient, B(22), previously reported for lysozyme and those estimated from k(rot).
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35
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McGuffee SR, Elcock AH. Atomically detailed simulations of concentrated protein solutions: the effects of salt, pH, point mutations, and protein concentration in simulations of 1000-molecule systems. J Am Chem Soc 2007; 128:12098-110. [PMID: 16967959 DOI: 10.1021/ja0614058] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An ability to accurately simulate the dynamic behavior of concentrated macromolecular solutions would be of considerable utility in studies of a wide range of biological systems. With this goal in mind, a Brownian dynamics (BD) simulation method is reported here that allows systems to be modeled that comprise in excess of 1000 protein molecules, all of which are treated in atomic detail. Intermolecular forces are described in the method using an energy function that incorporates electrostatic and hydrophobic interactions and that is calibrated to reproduce experimental thermodynamic information with a single adjustable parameter. Using the method, BD simulations have been performed over a wide range of pH and ionic strengths for three proteins: hen egg white lysozyme (HEWL), chymotrypsinogen, and T4 lysozyme. The simulations reproduce experimental trends in second virial coefficients (B(22)) and translational diffusion coefficients, correctly capture changes in B(22) values due to single amino acid substitutions, and reveal a new explanation for the difficulties reported previously in the literature in reproducing B(22) values for protein solutions of very low ionic strength. In addition, a strong correlation is found between a residue's probability of being involved in a protein-protein contact in the simulations and its probability of being involved in an experimental crystal contact. Finally, exploratory simulations of HEWL indicate that the simulation model also gives a promising description of behavior at very high protein concentrations (approximately 250 g/L), suggesting that it may provide a suitable computational framework for modeling the complex behavior exhibited by macromolecules in cellular conditions.
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Affiliation(s)
- Sean R McGuffee
- Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA
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36
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Jönsson M, Skepö M, Linse P. Monte Carlo simulations of the hydrophobic effect in aqueous electrolyte solutions. J Phys Chem B 2007; 110:8782-8. [PMID: 16640436 DOI: 10.1021/jp0604241] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hydrophobic interaction between two methane molecules in salt-free and high salt-containing aqueous solutions and the structure in such solutions have been investigated using an atomistic model solved by Monte Carlo simulations. Monovalent salt representing NaCl and divalent salt with the same nonelectrostatic properties as the monovalent salt have been used to examine the influence of the valence of the salt species. In salt-free solution the effective interaction between the two methane molecules displayed a global minimum at close contact of the two methane molecules and a solvent-separated secondary minimum. In 3 and 5 M monovalent salt solution the potential of mean force became slightly more attractive, and in a 3 M divalent salt solution the attraction became considerably stronger. The structure of the aqueous solutions was determined by radial distribution functions and angular probability functions. The distortion of the native water structure increased with ion valence. The increase of the hydrophobic attraction was associated with (i) a breakdown of the tetrahedral structure formed by neighboring water molecules and of the hydrogen bonds between them and (i) the concomitant increase of the solution density.
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Affiliation(s)
- Malin Jönsson
- Biochemistry and Physical Chemistry 1, Lund University, Box 124, SE-221 00 Lund, Sweden
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37
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Lo Nostro P, Ninham BW, Milani S, Lo Nostro A, Pesavento G, Baglioni P. Hofmeister effects in supramolecular and biological systems. Biophys Chem 2006; 124:208-13. [PMID: 16678961 DOI: 10.1016/j.bpc.2006.04.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 04/14/2006] [Accepted: 04/14/2006] [Indexed: 11/19/2022]
Abstract
Specific ion effects, representative of near-universal Hofmeister phenomena, are illustrated in three different systems. These are the formation of supramolecular assemblies from cyclodextrins, the optical rotation of L-serine, and the growth rate of two kinds of microorganisms (Staphylococcus aureus and Pseudomonas aeruginosa). The strong specific ion effects can be correlated with the anion polarizabilities and related physico-chemical parameters. The results show the relevance of dispersion (non-electrostatic) forces in these phenomena.
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Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy.
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38
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Ljungh A, Yanagisawa N, Wadström T. Using the principle of hydrophobic interaction to bind and remove wound bacteria. J Wound Care 2006; 15:175-80. [PMID: 16620048 DOI: 10.12968/jowc.2006.15.4.26901] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- A Ljungh
- Division of Bacteriology, Department Laboratory Medicine, Lund University, Sweden.
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39
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Shen VK, Cheung JK, Errington JR, Truskett TM. Coarse-grained strategy for modeling protein stability in concentrated solutions. II: phase behavior. Biophys J 2006; 90:1949-60. [PMID: 16387768 PMCID: PMC1386775 DOI: 10.1529/biophysj.105.076497] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Accepted: 12/08/2005] [Indexed: 11/18/2022] Open
Abstract
We use highly efficient transition-matrix Monte Carlo simulations to determine equilibrium unfolding curves and fluid phase boundaries for solutions of coarse-grained globular proteins. The model we analyze derives the intrinsic stability of the native state and protein-protein interactions from basic information about protein sequence using heteropolymer collapse theory. It predicts that solutions of low hydrophobicity proteins generally exhibit a single liquid phase near their midpoint temperatures for unfolding, while solutions of proteins with high sequence hydrophobicity display the type of temperature-inverted, liquid-liquid transition associated with aggregation processes of proteins and other amphiphilic molecules. The phase transition occurring in solutions of the most hydrophobic protein we study extends below the unfolding curve, creating an immiscibility gap between a dilute, mostly native phase and a concentrated, mostly denatured phase. The results are qualitatively consistent with the solution behavior of hemoglobin (HbA) and its sickle variant (HbS), and they suggest that a liquid-liquid transition resulting in significant protein denaturation should generally be expected on the phase diagram of high-hydrophobicity protein solutions. The concentration fluctuations associated with this transition could be a driving force for the nonnative aggregation that can occur below the midpoint temperature.
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Affiliation(s)
- Vincent K Shen
- Physical and Chemical Properties Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
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Curtis R, Lue L. A molecular approach to bioseparations: Protein–protein and protein–salt interactions. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2005.04.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Valente JJ, Verma KS, Manning MC, Wilson WW, Henry CS. Second virial coefficient studies of cosolvent-induced protein self-interaction. Biophys J 2005; 89:4211-8. [PMID: 16199499 PMCID: PMC1366986 DOI: 10.1529/biophysj.105.068551] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein self-interaction is important in protein crystal growth, solubilization, and aggregation, both in vitro and in vivo, as with protein misfolding diseases, such as Alzheimer's. Although second virial coefficient studies can supply invaluable quantitative information, their emergence as a systematic approach to evaluating protein self-interaction has been slowed by the limitations of traditional measurement methods, such as static light scattering. Comparatively, self-interaction chromatography is an inexpensive, high-throughput method of evaluating the osmotic second virial coefficient (B) of proteins in solution. In this work, we used self-interaction chromatography to measure B of lysozyme in the presence of various cosolvents, including sucrose, trehalose, mannitol, glycine, arginine, and combinations of arginine and glutamic acid and arginine and sucrose in an effort to develop a better fundamental understanding of protein self-interaction in complex cosolvent systems. All of these cosolvents, alone or in combination, increased B, indicating a reduction in intermolecular attraction. However, the magnitude of cosolvent-induced changes in B was found to be largely dependent on the ability to control long-range electrostatic repulsion. To the best of our knowledge, this work represents the most comprehensive virial coefficient study to date focusing on complex cosolvent-induced effects on the self-interaction of lysozyme.
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Affiliation(s)
- Joseph J Valente
- Department of Chemistry, Colorado State University, Fort Collins, Colorado, USA
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Cheung JK, Truskett TM. Coarse-grained strategy for modeling protein stability in concentrated solutions. Biophys J 2005; 89:2372-84. [PMID: 16040749 PMCID: PMC1366737 DOI: 10.1529/biophysj.105.062067] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present a coarse-grained approach for modeling the thermodynamic stability of single-domain globular proteins in concentrated aqueous solutions. Our treatment derives effective protein-protein interactions from basic structural and energetic characteristics of the native and denatured states. These characteristics, along with the intrinsic (i.e., infinite dilution) thermodynamics of folding, are calculated from elementary sequence information using a heteropolymer collapse theory. We integrate this information into Reactive Canonical Monte Carlo simulations to investigate the connections between protein sequence hydrophobicity, protein-protein interactions, protein concentration, and the thermodynamic stability of the native state. The model predicts that sequence hydrophobicity can affect how protein concentration impacts native-state stability in solution. In particular, low hydrophobicity proteins are primarily stabilized by increases in protein concentration, whereas high hydrophobicity proteins exhibit richer nonmonotonic behavior. These trends appear qualitatively consistent with the available experimental data. Although factors such as pH, salt concentration, and protein charge are also important for protein stability, our analysis suggests that some of the nontrivial experimental trends may be driven by a competition between destabilizing hydrophobic protein-protein attractions and entropic crowding effects.
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Affiliation(s)
- Jason K Cheung
- Department of Chemical Engineering, and Institute of Theoretical Chemistry, The University of Texas at Austin, Austin, TX 78712, USA
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Baier SK, McClements DJ. Influence of Cosolvent Systems on the Gelation Mechanism of Globular Protein: Thermodynamic, Kinetic, and Structural Aspects of Globular Protein Gelation. Compr Rev Food Sci Food Saf 2005; 4:43-54. [DOI: 10.1111/j.1541-4337.2005.tb00072.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kim UJ, Park J, Kim HJ, Wada M, Kaplan DL. Three-dimensional aqueous-derived biomaterial scaffolds from silk fibroin. Biomaterials 2005; 26:2775-85. [PMID: 15585282 DOI: 10.1016/j.biomaterials.2004.07.044] [Citation(s) in RCA: 673] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Accepted: 07/22/2004] [Indexed: 11/25/2022]
Abstract
A new all-aqueous process is described to form three-dimensional porous silk fibroin matrices with control of structural and morphological features. The result of this process are scaffolds with controllable porosity and pore sizes that fully degrade in the presence of proteases, unlike prior methods to generate silk-based biomaterials that required the use of organic solvent treatments to impart control of structure and stability in aqueous environments, with low rates of proteolytic hydrolysis. A mechanism is proposed for this novel process that imparts physical stability via hydrophobic interactions. Adjusting the concentration of silk fibroin in water, and the particle size of granular NaCl used in the process, leads to the control of morphological and functional properties of the scaffolds. The aqueous-derived scaffolds had highly homogeneous and interconnected pores with pore sizes ranging from 470 to 940 microm, depending on the mode of preparation. The scaffolds had porosities >90% and compressive strength and modulus up to 320 +/- 10 and 3330 +/- 500 KPa, respectively, when formed from 10% aqueous solutions of fibroin. The scaffolds fully degraded upon exposure to protease during 21 days, unlike the scaffolds prepared from organic solvent processing. These new silk-based three-dimensional matrices provide useful properties as biomaterial matrices due to the all-aqueous mode of preparation, control of pore size, connectivity of pores, degradability and useful mechanical features. Importantly, this process offers an entirely new window of materials properties when compared with traditional silk fibroin-based materials.
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Affiliation(s)
- Ung-Jin Kim
- Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155, USA
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45
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Lo Nostro P, Ninham BW, Lo Nostro A, Pesavento G, Fratoni L, Baglioni P. Specific ion effects on the growth rates ofStaphylococcus aureusandPseudomonas aeruginosa. Phys Biol 2005; 2:1-7. [PMID: 16204851 DOI: 10.1088/1478-3967/2/1/001] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Motivated by recent advances in the physical and chemical basis of the Hofmeister effect, we measured the rate cell growth of S. aureus--a halophilic pathogenic bacterium--and of P. aeruginosa, an opportunistic pathogen, in the presence of different aqueous salt solutions at different concentrations (0.2, 0.6 and 0.9 M). Microorganism growth rates depend strongly on the kind of anion in the growth medium. In the case of S. aureus, chloride provides a favorable growth medium, while both kosmotropes (water structure makers) and chaotropes (water structure breakers) reduce the microorganism growth. In the case of P. aeruginosa, all ions affect adversely the bacterial survival. In both cases, the trends parallel the specific ion, or Hofmeister, sequences observed in a wide range of physico-chemical systems. The correspondence with specific ion effect obtained in other studies, on the activities of a DNA restriction enzyme, of horseradish peroxidase, and of Lipase A (Aspergillus niger) is particularly striking. This work provides compelling evidence for Hofmeister effects, physical chemistry in action, in these organisms.
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Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3-50019 Sesto Fiorentino (Firenze), Italy.
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Kegel WK, Schoot Pv PVD. Competing hydrophobic and screened-coulomb interactions in hepatitis B virus capsid assembly. Biophys J 2004; 86:3905-13. [PMID: 15189887 PMCID: PMC1304292 DOI: 10.1529/biophysj.104.040055] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Accepted: 03/08/2004] [Indexed: 11/18/2022] Open
Abstract
Recent experiments show that, in the range from approximately 15 to 45 degrees C, an increase in the temperature promotes the spontaneous assembly into capsids of the Escherichia coli-expressed coat proteins of hepatitis B virus. Within that temperature interval, an increase in ionic strength up to five times that of standard physiological conditions also acts to promote capsid assembly. To explain both observations we propose an interaction of mean force between the protein subunits that is the sum of an attractive hydrophobic interaction, driving the self-assembly, and a repulsive electrostatic interaction, opposing the self-assembly. We find that the binding strength of the capsid subunits increases with temperature virtually independently of the ionic strength, and that, at fixed temperature, the binding strength increases with the square root of ionic strength. Both predictions are in quantitative agreement with experiment. We point out the similarities of capsid assembly in general and the micellization of surfactants. Finally we make plausible that electrostatic repulsion between the native core subunits of a large class of virus suppresses the formation in vivo of empty virus capsids, that is, without the presence of the charge-neutralizing nucleic acid.
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Affiliation(s)
- Willem K Kegel
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University, Utrecht, The Netherlands.
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Liu W, Bratko D, Prausnitz JM, Blanch HW. Effect of alcohols on aqueous lysozyme–lysozyme interactions from static light-scattering measurements. Biophys Chem 2004; 107:289-98. [PMID: 14967244 DOI: 10.1016/j.bpc.2003.09.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Accepted: 09/22/2003] [Indexed: 10/26/2022]
Abstract
Alcohols have been widely used as protein denaturants, precipitants and crystallization reagents. We have studied the effect of alcohols on aqueous hen-egg lysozyme self-interactions by measuring the osmotic second virial coefficient (B22) using static light scattering. Addition of alcohols increases B22, indicating stronger protein-protein repulsion or weaker attraction. For the monohydric alcohols used in this study (methanol, ethanol, 1-propanol, n-butanol, iso-butanol and trifluoroethanol), B22 for lysozyme reaches a common plateau at approximately 5% (v/v) alcohol, while glycerol increases B22 more than monohydric alcohols. For a 0.05 M NaCl hen-egg lysozyme solution at pH 7, B22 increases from 2.4 x 10(-4) to 4.7 x 10(-4) ml mol/g2 upon addition of monohydric alcohols and to 5.8 x 10(-4) ml mol/g2 upon addition of glycerol. We describe the alcohol effect using a simple model that supplements the DLVO theory with an additional alcohol-dependent term representing orientation-averaged hydrophobic interactions. In this model, the increased lysozyme repulsive forces in the presence of monohydric alcohols are interpreted in terms of adsorption of alcohol molecules on hydrophobic sites on the protein surface. This adsorption reduces attractive hydrophobic protein-protein interactions. A thicker lysozyme hydration layer in aqueous glycerol solution can explain the glycerol-increased lysozyme-lysozyme repulsion.
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Affiliation(s)
- Wei Liu
- Chemical Engineering Department, University of California, Berkeley, CA 94720, USA
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Piazza R, Iacopini S, Triulzi B. Thermophoresis as a probe of particle–solvent interactions: The case of protein solutions. Phys Chem Chem Phys 2004. [DOI: 10.1039/b312856c] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Ho JGS, Middelberg APJ. The influence of molecular variation on protein interactions. Biotechnol Bioeng 2003; 84:611-6. [PMID: 14574695 DOI: 10.1002/bit.10815] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We investigated the influence of solvation forces on protein-protein interactions for two forms of lysozyme: hen egg white (HEWL) and turkey egg white (TEWL). Turkey egg white has more surface exposed hydrophobic residues than HEWL and the protein-protein interactions of TEWL are shown to be more attractive than those of HEWL, for the conditions studied. The importance of including a solvation term in the potential of mean force model, to account for molecular variation in protein surface characteristics, is highlighted. We also show that the magnitude of this solvation term can be estimated using readily available data.
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Affiliation(s)
- Jason G S Ho
- Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
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Chang BH, Bae YC. Lysozyme−Lysozyme and Lysozyme−Salt Interactions in the Aqueous Saline Solution: A New Square-Well Potential. Biomacromolecules 2003; 4:1713-8. [PMID: 14606900 DOI: 10.1021/bm0300406] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigate lysozyme-lysozyme and lysozyme-salt interactions in electrolyte solutions using a molecular-thermodynamic model. An equation of state based on the statistical mechanical perturbation theory is applied to describe the interactions. The perturbation term includes a new square-well potential of mean force, which implies the information about the lysozyme surface and salt type. The attractive energy of the potential of mean force is correlated with experimental cloud-point temperatures of lysozyme in various solution conditions. The same attractive energy is used to predict osmotic pressure of a given system with no additional parameters. The new potential shows a satisfactory improvement in understanding the interactions between lysozymes in aqueous salt solutions.
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Affiliation(s)
- Bong Ho Chang
- Division of Chemical Engineering and Molecular Thermodynamics Lab., Hanyang University, Seoul 133-791, Korea
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