1
|
Enomoto K, Torisu T, Mizuguchi J, Tanoue R, Uchiyama S. Structure of Human Serum Albumin at a Foam Surface. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:8774-8783. [PMID: 38587054 DOI: 10.1021/acs.jafc.3c09357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Proteins can be adsorbed on the air-water interface (AWI), and the structural changes in proteins at the AWI are closely related to the foaming properties of foods and beverages. However, how these structural changes in proteins at the AWI occur is not well understood. We developed a method for the structural assessment of proteins in the foam state using hydrogen/deuterium exchange mass spectrometry. Adsorption sites and structural changes in human serum albumin (HSA) were identified in situ at the peptide-level resolution. The N-terminus and the loop (E492-T506), which contains hydrophobic amino acids, were identified as adsorption sites. Both the structural flexibility and hydrophobicity were considered to be critical factors for the adsorption of HSA at the AWI. Structural changes in HSA were observed after more than one minute of foaming and were spread widely throughout the structure. These structural changes at the foam AWI were reversible.
Collapse
Affiliation(s)
- Kanta Enomoto
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tetsuo Torisu
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Junya Mizuguchi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ryosuke Tanoue
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Susumu Uchiyama
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Exploratory Research Center on Life andLiving Systems, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| |
Collapse
|
2
|
Han F, Shen Q, Zheng W, Zuo J, Zhu X, Li J, Peng C, Li B, Chen Y. The Conformational Changes of Bovine Serum Albumin at the Air/Water Interface: HDX-MS and Interfacial Rheology Analysis. Foods 2023; 12:foods12081601. [PMID: 37107396 PMCID: PMC10137346 DOI: 10.3390/foods12081601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/03/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
The characterization and dynamics of protein structures upon adsorption at the air/water interface are important for understanding the mechanism of the foamability of proteins. Hydrogen-deuterium exchange, coupled with mass spectrometry (HDX-MS), is an advantageous technique for providing conformational information for proteins. In this work, an air/water interface, HDX-MS, for the adsorbed proteins at the interface was developed. The model protein bovine serum albumin (BSA) was deuterium-labeled at the air/water interface in situ for different predetermined times (10 min and 4 h), and then the resulting mass shifts were analyzed by MS. The results indicated that peptides 54-63, 227-236, and 355-366 of BSA might be involved in the adsorption to the air/water interface. Moreover, the residues L55, H63, R232, A233, L234, K235, A236, R359, and V366 of these peptides might interact with the air/water interface through hydrophobic and electrostatic interactions. Meanwhile, the results showed that conformational changes of peptides 54-63, 227-236, and 355-366 could lead to structural changes in their surrounding peptides, 204-208 and 349-354, which could cause the reduction of the content of helical structures in the rearrangement process of interfacial proteins. Therefore, our air/water interface HDX-MS method could provide new and meaningful insights into the spatial conformational changes of proteins at the air/water interface, which could help us to further understand the mechanism of protein foaming properties.
Collapse
Affiliation(s)
- Fei Han
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qian Shen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wei Zheng
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jingnan Zuo
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xinyu Zhu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jingwen Li
- National Facility for Protein Science in Shanghai, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Chao Peng
- National Facility for Protein Science in Shanghai, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Bin Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yijie Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Wuhan 430070, China
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China
| |
Collapse
|
3
|
Kopp MRG, Grigolato F, Zürcher D, Das TK, Chou D, Wuchner K, Arosio P. Surface-Induced Protein Aggregation and Particle Formation in Biologics: Current Understanding of Mechanisms, Detection and Mitigation Strategies. J Pharm Sci 2023; 112:377-385. [PMID: 36223809 DOI: 10.1016/j.xphs.2022.10.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 10/05/2022] [Accepted: 10/05/2022] [Indexed: 01/12/2023]
Abstract
Protein stability against aggregation is a major quality concern for the production of safe and effective biopharmaceuticals. Amongst the different drivers of protein aggregation, increasing evidence indicates that interactions between proteins and interfaces represent a major risk factor for the formation of protein aggregates in aqueous solutions. Potentially harmful surfaces relevant to biologics manufacturing and storage include air-water and silicone oil-water interfaces as well as materials from different processing units, storage containers, and delivery devices. The impact of some of these surfaces, for instance originating from impurities, can be difficult to predict and control. Moreover, aggregate formation may additionally be complicated by the simultaneous presence of interfacial, hydrodynamic and mechanical stresses, whose contributions may be difficult to deconvolute. As a consequence, it remains difficult to identify the key chemical and physical determinants and define appropriate analytical methods to monitor and predict protein instability at these interfaces. In this review, we first discuss the main mechanisms of surface-induced protein aggregation. We then review the types of contact materials identified as potentially harmful or detected as potential triggers of proteinaceous particle formation in formulations and discuss proposed mitigation strategies. Finally, we present current methods to probe surface-induced instabilities, which represent a starting point towards assays that can be implemented in early-stage screening and formulation development of biologics.
Collapse
Affiliation(s)
- Marie R G Kopp
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Fulvio Grigolato
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Dominik Zürcher
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | | | | | | | - Paolo Arosio
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland.
| |
Collapse
|
4
|
Inactivation of Endogenous Pectin Methylesterases by Radio Frequency Heating during the Fermentation of Fruit Wines. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8060265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Pectin methylesterase (PME) is a methyl ester group hydrolytic enzyme of either plant or microbial origin. Importantly, endogenous PMEs in fruits can catalyze the demethoxylation of pectin with a bulk release of methanol, largely impacting the fruit juice and wine industries. Here, we demonstrated radio frequency (RF) heating for inactivation of endogenous PMEs and investigated the relevant mechanisms underpinning enzymatic inactivation. The RF heating curve indicated that the optimal heating rate was achieved at an electrode gap of 90 mm (compared to 100 mm and 110 mm) and that the inactivation rate of the enzyme increases with heating time. RF heating exhibited better effects on enzymatic inactivation than traditional water heating, mainly by changing the secondary structures of PMEs, including α-helix, β-sheet, β-turn, and random coil. Moreover, fluorescence spectroscopy indicated changes in the tertiary structure with a significant increase in fluorescence intensity. Significantly, application of RF heating for inactivation of PMEs resulted in a 1.5-fold decrease in methanol during the fermentation of jujube wine. Collectively, our findings demonstrated an effective approach for inactivating endogenous PMEs during the bioprocesses of fruits.
Collapse
|
5
|
Milyaeva OY, Rafikova AR. Effect of Low Concentrations of Thrombin on the Dynamic Surface Properties of Fibrinogen Solutions. COLLOID JOURNAL 2022. [DOI: 10.1134/s1061933x22010070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
6
|
Chen Y, Zhai MJ, Mehwish N, Xu MD, Wang Y, Gong YX, Ren MM, Deng H, Lee BH. Comparison of globular albumin methacryloyl and random-coil gelatin methacryloyl: Preparation, hydrogel properties, cell behaviors, and mineralization. Int J Biol Macromol 2022; 204:692-708. [PMID: 35150780 DOI: 10.1016/j.ijbiomac.2022.02.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 12/19/2022]
Abstract
Bovine serum albumin methacryloyl (BSAMA) is a newly emerging photocurable globular protein-based material whereas gelatin methacryloyl (GelMA) is one of the most popular photocurable fibrous protein-based materials. So far, the influence of their different structural conformations as building blocks on hydrogel properties and mineral deposition has not been investigated. Here, we compared their differences in structures, gelation kinetics, hydrogel properties, mineralization, and cell behaviors. BSAMA maintained a stable globular structure while GelMA exhibited temperature-sensitive conformations (4 - 37 °C). BSAMA displayed slower gelation kinetics and much more retarded enzymatic degradation compared to GelMA. Photocurable BSAMA (6.41 - 390.95 kPa) and GelMA hydrogels (36.09 - 199.70 kPa) exhibited tunable mechanical properties depending on their concentrations (10 - 20%). Interestingly, BSAMA hydrogels mineralized needle-like apatite (Ca/P: 1.409) with higher crystallinity compared to GelMA hydrogels (Ca/P: 1.344). BSAMA and GelMA supported satisfactory cell (MC3T3-L1) viability of 99.43 ± 0.57% and 97.14 ± 0.69%, respectively. However, BSAMA gels were less favorable to cell proliferation and migration than GelMA gels. In serum-free environments, cells on GelMA displayed a higher amount of attachment, a more elongated shape, and a longer protrusion compared to those on BSAMA (p < 0.01) during the early adhesion.
Collapse
Affiliation(s)
- Yuan Chen
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325011, China; Department of Periodontics, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Meng Jiao Zhai
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325011, China
| | - Nabila Mehwish
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325011, China
| | - Meng Die Xu
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325011, China
| | - Yi Wang
- Department of Orthodontics, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yi Xuan Gong
- Department of Periodontics, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Man Man Ren
- Department of Periodontics, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Hui Deng
- Department of Periodontics, School & Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
| | - Bae Hoon Lee
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325011, China; Oujiang Laboratory (Zhejiang Lab for Rengerative Medicine, Vision and Brain Health), Wenzhou, Zhejiang 325001, China.
| |
Collapse
|
7
|
Park K, Ham BY, Li K, Kang S, Jung D, Kim H, Liu Y, Hwang I, Lee J. Insights into the enhanced thermal stability of lysozyme with altered structure and activity induced by choline chloride-based deep eutectic solvents containing polyols and sugars. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|
8
|
Kanthe A, Ilott A, Krause M, Zheng S, Li J, Bu W, Bera MK, Lin B, Maldarelli C, Tu RS. No ordinary proteins: Adsorption and molecular orientation of monoclonal antibodies. SCIENCE ADVANCES 2021; 7:eabg2873. [PMID: 34452912 PMCID: PMC8397265 DOI: 10.1126/sciadv.abg2873] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/07/2021] [Indexed: 06/12/2023]
Abstract
The interaction of monoclonal antibodies (mAbs) with air/water interfaces plays a crucial role in their overall stability in solution. We aim to understand this behavior using pendant bubble measurements to track the dynamic tension reduction and x-ray reflectivity to obtain the electron density profiles (EDPs) at the surface. Native immunoglobulin G mAb is a rigid molecule with a flat, "Y" shape, and simulated EDPs are obtained by rotating a homology construct at the surface. Comparing simulations with experimental EDPs, we obtain surface orientation probability maps showing mAbs transition from flat-on Y-shape configurations to side-on or end-on configurations with increasing concentration. The modeling also shows the presence of β sheets at the surface. Overall, the experiments and the homology modeling elucidate the orientational phase space during different stages of adsorption of mAbs at the air/water interface. These finding will help define new strategies for the manufacture and storage of antibody-based therapeutics.
Collapse
Affiliation(s)
- Ankit Kanthe
- Department of Chemical Engineering, The City College of New York, New York, NY 10031, USA
| | - Andrew Ilott
- Drug Product Development, Bristol Myers Squibb, New Brunswick, NJ 08901, USA
| | - Mary Krause
- Drug Product Development, Bristol Myers Squibb, New Brunswick, NJ 08901, USA
| | - Songyan Zheng
- Drug Product Development, Bristol Myers Squibb, New Brunswick, NJ 08901, USA
| | - Jinjiang Li
- Pharmaceutical Development, Wolfe Laboratories, Watertown, MA, 01801, USA
| | - Wei Bu
- NSF's ChemMatCARS, Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 606371, USA
| | - Mrinal K Bera
- NSF's ChemMatCARS, Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 606371, USA
| | - Binhua Lin
- NSF's ChemMatCARS, Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 606371, USA
| | - Charles Maldarelli
- Department of Chemical Engineering, The City College of New York, New York, NY 10031, USA.
- Levich Institute, The City College of New York, New York, NY 10031, USA
| | - Raymond S Tu
- Department of Chemical Engineering, The City College of New York, New York, NY 10031, USA.
| |
Collapse
|
9
|
|
10
|
Guckeisen T, Hosseinpour S, Peukert W. Effect of pH and urea on the proteins secondary structure at the water/air interface and in solution. J Colloid Interface Sci 2021; 590:38-49. [PMID: 33524719 DOI: 10.1016/j.jcis.2021.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 01/09/2023]
Abstract
HYPOTHESIS The secondary structure of proteins affects their functionality and performance in physiological environments or industrial applications. Change of the solution pH or the presence of protein denaturants are the main chemical means that can alter the secondary structure of proteins or lead to protein denaturation. Since proteins in the bulk solution and those residing at the solution/air interface experience different local environments, their response to chemical denaturation can be different. EXPERIMENTS We utilize circular dichroism and chiral/achiral sum frequency generation spectroscopy to study the secondary structure of selected proteins as a function of the solution pH or in the presence of 8 M urea in the bulk solution and at the solution/air interface, respectively. FINDINGS The liquid/air interface can enhance or decrease protein conformation stability. The change in the secondary structure of the surface adsorbed proteins in alkaline solutions occurs at pH values lower than those denaturing the studied proteins in the bulk solution. In contrast, while 8 M urea completely denatures the studied proteins in the bulk solution, the liquid/air interface prevents the urea-induced denaturation of the surface adsorbed proteins by limiting the access of urea to the hydrophobic side chains of proteins protruding to air.
Collapse
Affiliation(s)
- Tobias Guckeisen
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| |
Collapse
|
11
|
Alamdari S, Roeters SJ, Golbek TW, Schmüser L, Weidner T, Pfaendtner J. Orientation and Conformation of Proteins at the Air-Water Interface Determined from Integrative Molecular Dynamics Simulations and Sum Frequency Generation Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11855-11865. [PMID: 32921055 DOI: 10.1021/acs.langmuir.0c01881] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the assembly of proteins at the air-water interface (AWI) informs the formation of protein films, emulsion properties, and protein aggregation. Determination of protein conformation and orientation at an interface is difficult to resolve with a single experimental or simulation technique alone. To date, the interfacial structure of even one of the most widely studied proteins, lysozyme, at the AWI remains unresolved. In this study, molecular dynamics (MD) simulations are used to determine if the protein adopts a side-on, head-on, or axial orientation at the AWI with two different forcefields, GROMOS-53a6 + SPC/E and a99SB-disp + TIP4P-D. Vibrational sum frequency generation (SFG) spectroscopy experiments and spectral SFG calculations validate consistency between the structure determined from MD and experiments. Overall, we show with strong agreement that lysozyme adopts an axial conformation at pH 7. Further, we provide molecular-level insight as to how pH influences the binding domains of lysozyme resulting in side-on adsorption near the isoelectric point of the lysozyme.
Collapse
Affiliation(s)
- Sarah Alamdari
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750, United States
| | - Steven J Roeters
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Thaddeus W Golbek
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Lars Schmüser
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Tobias Weidner
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Jim Pfaendtner
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750, United States
| |
Collapse
|
12
|
Wang J, Zheng X, Zhang H. Exploring the conformational changes in fibrinogen by forming protein corona with CdTe quantum dots and the related cytotoxicity. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 220:117143. [PMID: 31136867 DOI: 10.1016/j.saa.2019.117143] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/04/2019] [Accepted: 05/17/2019] [Indexed: 06/09/2023]
Abstract
This study describes synthesis of N‑acetyl‑l‑cysteine-capped CdTe quantum dots (QDs) and investigates their interaction with plasma protein fibrinogen (FIB) and the structural changes of FIB. It is shown that the interaction of QDs with FIB is a spontaneous process and the major driving forces are van der Waals forces and hydrogen bonds. Multi-spectroscopic measurements show that the intrinsic fluorescence of FIB was quenched and secondary and tertiary structures were altered due to the interaction with QDs. In addition, the aggregation state of FIB was altered in the presence of QDs. Furthermore, the formed complexes of FIB with QDs reduced the cytotoxicity of QDs. The coating of FIB on QDs could lower intracellular QDs uptake and therefore result in less released cadmium ions and ROS productions. This study, therefore, might be helpful to the comprehensive understanding of QDs toxicity and provide evidence for assessing the safe application of nanoparticles.
Collapse
Affiliation(s)
- Jing Wang
- School of Environmental and Material Engineering, Yantai University, 30# Qingquan Road, Yantai 264005, PR China.
| | - Xiaolin Zheng
- School of Environmental and Material Engineering, Yantai University, 30# Qingquan Road, Yantai 264005, PR China
| | - Hongfa Zhang
- School of Environmental and Material Engineering, Yantai University, 30# Qingquan Road, Yantai 264005, PR China
| |
Collapse
|
13
|
Blas P, Tolner B, Ward J, Chester K, Hoare M. The use of a surface active agent in the protection of a fusion protein during bioprocessing. Biotechnol Bioeng 2018; 115:2760-2770. [PMID: 30102764 PMCID: PMC6334174 DOI: 10.1002/bit.26817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/29/2018] [Accepted: 07/23/2018] [Indexed: 11/14/2022]
Abstract
The bioprocessing of a fusion protein is characterised by low yields and at a series of recovery and purification stages that leads to an overall 90% loss. Much of this apparent loss is due to the denaturation of a protein, missing a vital affinity ligand. However, there is evidence of the protection of degradation products which occurs in the presence of shear plus air/liquid interfaces. This study seeks out to characterise the loss and use ultra‐scale‐down studies to predict its occurrence and hence shows these may be diminished by the use of protective reagents such as Pluronic F68.
Collapse
Affiliation(s)
- Peter Blas
- Department of Biochemical Engineering, ACBE, University College London, London, UK
| | - Berend Tolner
- Department of Oncology, The Royal Free Hospital, London, UK
| | - John Ward
- Department of Biochemical Engineering, ACBE, University College London, London, UK
| | - Kerry Chester
- Department of Oncology, The Royal Free Hospital, London, UK
| | - Mike Hoare
- Department of Biochemical Engineering, ACBE, University College London, London, UK
| |
Collapse
|
14
|
Milyaeva O, Gochev G, Loglio G, Miller R, Noskov B. Influence of polyelectrolytes on dynamic surface properties of fibrinogen solutions. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
15
|
Noskov BA, Krycki MM. Formation of protein/surfactant adsorption layer as studied by dilational surface rheology. Adv Colloid Interface Sci 2017; 247:81-99. [PMID: 28716186 DOI: 10.1016/j.cis.2017.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/19/2017] [Accepted: 07/02/2017] [Indexed: 12/25/2022]
Abstract
The review discusses the mechanism of formation of protein/surfactant adsorption layers at the liquid - gas interface. The complexes of globular proteins usually preserve their compact structure a low surfactant concentrations. Therefore a simple kinetic model of the adsorption of charged compact nanoparticles is discussed first and compared with experimental data. The increase of surfactant concentrations results in various conformational transitions in the surface layer. One can obtain information on the changes of the adsorption layer structure using the dilational surface rheology. The kinetic dependencies of the dynamic surface elasticity are strongly different for the adsorption of unfolded macromolecules and compact globules, and have local maxima in the former case corresponding to different steps of the adsorption. These distinctions allow tracing the changes of the tertiary structure of protein/surfactant complexes in the surface layer. The adsorption from mixed solutions of ionic surfactants with β-casein, β-lactoglobulin, bovine serum albumin and myoglobin is discussed with some details.
Collapse
|
16
|
Schöne AC, Roch T, Schulz B, Lendlein A. Evaluating polymeric biomaterial-environment interfaces by Langmuir monolayer techniques. J R Soc Interface 2017; 14:20161028. [PMID: 28468918 PMCID: PMC5454283 DOI: 10.1098/rsif.2016.1028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/05/2017] [Indexed: 12/18/2022] Open
Abstract
Polymeric biomaterials are of specific relevance in medical and pharmaceutical applications due to their wide range of tailorable properties and functionalities. The knowledge about interactions of biomaterials with their biological environment is of crucial importance for developing highly sophisticated medical devices. To achieve optimal in vivo performance, a description at the molecular level is required to gain better understanding about the surface of synthetic materials for tailoring their properties. This is still challenging and requires the comprehensive characterization of morphological structures, polymer chain arrangements and degradation behaviour. The review discusses selected aspects for evaluating polymeric biomaterial-environment interfaces by Langmuir monolayer methods as powerful techniques for studying interfacial properties, such as morphological and degradation processes. The combination of spectroscopic, microscopic and scattering methods with the Langmuir techniques adapted to polymers can substantially improve the understanding of their in vivo behaviour.
Collapse
Affiliation(s)
- Anne-Christin Schöne
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
| | - Toralf Roch
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
- Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Kantstrasse 55, 14513 Teltow, Germany
| | - Burkhard Schulz
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
| | - Andreas Lendlein
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
- Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Kantstrasse 55, 14513 Teltow, Germany
| |
Collapse
|
17
|
HU histone-like DNA-binding protein from Thermus thermophilus: structural and evolutionary analyses. Extremophiles 2016; 20:695-709. [DOI: 10.1007/s00792-016-0859-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022]
|
18
|
Noskov BA, Bykov AG. Dilational surface rheology of polymer solutions. RUSSIAN CHEMICAL REVIEWS 2015. [DOI: 10.1070/rcr4518] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
19
|
Wang Y, Deng H, Huangfu C, Lu Z, Wang X, Zeng X, He H, Rao H. Research of protein adsorption on the different surface topography of the zinc oxide. SURF INTERFACE ANAL 2014. [DOI: 10.1002/sia.5698] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yanying Wang
- College of Science; Sichuan Agricultural University; Ya'an 625014 PR China
| | - Hao Deng
- State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials; Southwest University of Science and Technology; Mianyang 621010 PR China
| | - Changxin Huangfu
- College of Science; Sichuan Agricultural University; Ya'an 625014 PR China
| | - Zhiwei Lu
- College of Science; Sichuan Agricultural University; Ya'an 625014 PR China
| | - Xianxiang Wang
- College of Science; Sichuan Agricultural University; Ya'an 625014 PR China
| | - Xianyin Zeng
- College of Life Science; Sichuan Agricultural University; Ya'an 625014 PR China
| | - Hua He
- Animal Genetics and Breeding Institute of Sichuan Agricultural University; Sichuan Ya'An 625014 PR China
| | - Hanbing Rao
- College of Science; Sichuan Agricultural University; Ya'an 625014 PR China
| |
Collapse
|
20
|
Huang T, Cao C, Liu ZL, Li Y, Du FP. Interaction of pepsin-[C16mim]Br system: interfacial dilational rheology and conformational studies. SOFT MATTER 2014; 10:6810-6819. [PMID: 25079107 DOI: 10.1039/c4sm00950a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interfacial rheological property is closely related to the stabilities of foams and emulsions, yet there have been limited studies on the interaction between proteins with ionic liquid-type imidazolium surfactants at the decane-water interface as well as in the bulk. Herein, we investigated the interfacial and bulk properties of pepsin (PEP) and an ionic liquid (IL), 1-hexadecyl-3-methylimidazolium bromide, [C(16)mim]Br. The interfacial pressure and dilational rheology studies were performed to describe the formation of [C(16)mim]Br-pepsin complexes. The influence of the oscillating frequency and the bulk concentration of [C(16)mim]Br on the dilational properties were explored. The conformational changes were studied by monitoring the fluorescence and far UV-CD spectra. The results reveal that the globular structure of pepsin is one of the decisive factors controlling the nature of the interfacial film. The monotonous increase in the dilational elastic modulus of pepsin-[C(16)mim]Br solutions with the surface age indicates that no loops and tails had formed. Interestingly, with an increase in the concentration of [C(16)mim]Br, the εd-c curve first passes through a plateau value due to steric hindrance and the electrostatic barrier of already absorbed tenacious pepsin-[C(16)mim]Br complexes. With the further addition of [C(16)mim]Br, the remarkable decrease in dilational elastic modulus indicates that the compact structure is destroyed gradually. The results of the fluorescence spectra and far UV-CD spectra confirm that [C(16)mim]Br did not produce perceptible changes in pepsin at the concentrations studied in the dilational experiment. Possible schematic programs of the pepsin-[C(16)mim]Br interaction model at the interface and in bulk phase are proposed.
Collapse
Affiliation(s)
- Tian Huang
- Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, P. R. China.
| | | | | | | | | |
Collapse
|
21
|
Protein conformational transitions at the liquid-gas interface as studied by dilational surface rheology. Adv Colloid Interface Sci 2014; 206:222-38. [PMID: 24238394 DOI: 10.1016/j.cis.2013.10.024] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 10/21/2013] [Accepted: 10/21/2013] [Indexed: 11/21/2022]
Abstract
Experimental results on the dynamic dilational surface elasticity of protein solutions are analyzed and compared. Short reviews of the protein behavior at the liquid-gas interface and the dilational surface rheology precede the main sections of this work. The kinetic dependencies of the surface elasticity differ strongly for the solutions of globular and non-globular proteins. In the latter case these dependencies are similar to those for solutions of non-ionic amphiphilic polymers and have local maxima corresponding to the formation of the distal region of the surface layer (type I). In the former case the dynamic surface elasticity is much higher (>60 mN/m) and the kinetic dependencies are monotonical and similar to the data for aqueous dispersions of solid nanoparticles (type II). The addition of strong denaturants to solutions of bovine serum albumin and β-lactoglobulin results in an abrupt transition from the type II to type I dependencies if the denaturant concentration exceeds a certain critical value. These results give a strong argument in favor of the preservation of the protein globular structure in the course of adsorption without any denaturants. The addition of cationic surfactants also can lead to the non-monotonical kinetic dependencies of the dynamic surface elasticity indicating destruction of the protein tertiary and secondary structures. The addition of anionic surfactants gives similar results only for the protein solutions of high ionic strength. The influence of cationic surfactants on the local maxima of the kinetic dependencies of the dynamic surface elasticity for solutions of a non-globular protein (β-casein) differs from the influence of anionic surfactants due to the heterogeneity of the charge distribution along the protein chain. In this case one can use small admixtures of ionic surfactants as probes of the adsorption mechanism. The effect of polyelectrolytes on the kinetic dependencies of the dynamic surface elasticity of protein solutions is weaker than the effect of conventional surfactants but exceeds the error limits.
Collapse
|
22
|
Day L, Zhai J, Xu M, Jones NC, Hoffmann SV, Wooster TJ. Conformational changes of globular proteins adsorbed at oil-in-water emulsion interfaces examined by Synchrotron Radiation Circular Dichroism. Food Hydrocoll 2014. [DOI: 10.1016/j.foodhyd.2012.12.015] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
23
|
Bobály B, Tóth E, Drahos L, Zsila F, Visy J, Fekete J, Vékey K. Influence of acid-induced conformational variability on protein separation in reversed phase high performance liquid chromatography. J Chromatogr A 2014; 1325:155-62. [DOI: 10.1016/j.chroma.2013.12.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 12/03/2013] [Accepted: 12/06/2013] [Indexed: 12/23/2022]
|
24
|
|
25
|
Fears KP, Petrovykh DY, Photiadis SJ, Clark TD. Circular dichroism analysis of cyclic β-helical peptides adsorbed on planar fused quartz. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:10095-10101. [PMID: 23845110 DOI: 10.1021/la401544c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Conformational changes of three cyclic β-helical peptides upon adsorption onto planar fused-quartz substrates were detected and analyzed by far-ultraviolet (UV) circular dichroism (CD) spectroscopy. In trifluoroethanol (TFE), hydrophobic peptides, Leu β and Val β, form left- and right-handed helices, respectively, and water-soluble peptide WS β forms a left-handed helix. Upon adsorption, CD spectra showed a mixture of folded and unfolded conformations for Leu β and Val β and predominantly unfolded conformations for WS β. X-ray photoelectron spectroscopy (XPS) provided insight about the molecular mechanisms governing the conformational changes, revealing that ca. 40% of backbone amides in Leu β and Val β were interacting with the hydrophilic substrate, while only ca. 15% of the amines/amides in WS β showed similar interactions. In their folded β-helical conformations, Leu β and Val β present only hydrophobic groups to their surroundings; hydrophilic surface groups can only interact with backbone amides if the peptides change their conformation. Conversely, as a β helix, WS β presents hydrophilic side chains to its surroundings that could, in principle, interact with hydrophilic surface groups, with the peptide retaining its folded structure. Instead, the observed unfolded surface conformation for WS β and the relatively small percentage of surface-bound amides (15 versus 40% for Leu β and Val β) suggest that hydrophilic surface groups induce unfolding. Upon this surface-induced unfolding, WS β interacts with the surface preferentially via hydrophilic side chains rather than backbone amides. In contrast, the unfolded β-hairpin-like form of WS β does not irreversibly adsorb on fused quartz from water, highlighting that solvation effects can be more important than initial conformation in governing peptide adsorption. Both label-free methods demonstrated in this work are, in general, applicable to structural analysis of a broad range of biomolecules adsorbed on transparent planar substrates, the surface properties of which could be customized.
Collapse
Affiliation(s)
- Kenan P Fears
- Division of Chemistry, Naval Research Laboratory, Washington, District of Columbia 20375, United States.
| | | | | | | |
Collapse
|
26
|
Yano YF. Kinetics of protein unfolding at interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:503101. [PMID: 23164927 DOI: 10.1088/0953-8984/24/50/503101] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The conformation of protein molecules is determined by a balance of various forces, including van der Waals attraction, electrostatic interaction, hydrogen bonding, and conformational entropy. When protein molecules encounter an interface, they are often adsorbed on the interface. The conformation of an adsorbed protein molecule strongly depends on the interaction between the protein and the interface. Recent time-resolved investigations have revealed that protein conformation changes during the adsorption process due to the protein-protein interaction increasing with increasing interface coverage. External conditions also affect the protein conformation. This review considers recent dynamic observations of protein adsorption at various interfaces and their implications for the kinetics of protein unfolding at interfaces.
Collapse
Affiliation(s)
- Yohko F Yano
- Department of Physics, Kinki University, Higashiosaka City, Osaka, Japan.
| |
Collapse
|
27
|
Qu Z, Ding J. Physical modification of the interior surfaces of PLGA porous scaffolds using sugar fibers as template. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 24:447-59. [DOI: 10.1080/09205063.2012.690285] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Zehua Qu
- a State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science , Laboratory of Advanced Materials, Fudan University , Shanghai , 200433 , China
| | - Jiandong Ding
- a State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science , Laboratory of Advanced Materials, Fudan University , Shanghai , 200433 , China
| |
Collapse
|
28
|
Noskov BA, Tikhonov MM. Effect of sodium dodecyl sulfate on dynamic surface properties of lysozyme solutions. COLLOID JOURNAL 2012. [DOI: 10.1134/s1061933x12020081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
29
|
Sivaraman B, Latour RA. Time-dependent conformational changes in adsorbed albumin and its effect on platelet adhesion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:2745-52. [PMID: 22191731 PMCID: PMC3286649 DOI: 10.1021/la204777x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Recent studies have shown that platelets can adhere to adsorbed albumin (Alb) through a receptor-mediated mechanism, but only if the Alb undergoes more than a critical degree of adsorption-induced unfolding. The objectives of this research were to investigate whether Alb that was initially adsorbed in a manner that induced unfolding that was less than this critical level would undergo further unfolding with time and, if so, whether this would induce the onset of platelet adhesion once this critical level was exceeded. To address these questions, CD spectropolarimetry was used to monitor the structure of Alb on OH- and CH(3)-functionalized alkanethiol self-assembled monolayer surfaces, with the Alb initially adsorbed under conditions resulting in degrees of unfolding that were below this critical level, and then the adsorbed Alb layers were aged over 6 months in sterile physiological saline at 37 °C. Platelet adhesion to Alb was quantified at selected time points via a lactate dehydrogenase (LDH) assay. The results indicate that an adsorbed Alb layer does undergo further structural changes with increasing residence time and supports platelet adhesion once it unfolds beyond the previously determined critical level. These results may be relevant to the clinically observed problem of the onset of late-thrombosis, which occurs on cardiovascular implants such as drug-eluting stents.
Collapse
|
30
|
Desfougères Y, Saint-Jalmes A, Salonen A, Vié V, Beaufils S, Pezennec S, Desbat B, Lechevalier V, Nau F. Strong improvement of interfacial properties can result from slight structural modifications of proteins: the case of native and dry-heated lysozyme. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14947-14957. [PMID: 22040020 DOI: 10.1021/la203485y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Identification of the key physicochemical parameters of proteins that determine their interfacial properties is still incomplete and represents a real stake challenge, especially for food proteins. Many studies have thus consisted in comparing the interfacial behavior of different proteins, but it is difficult to draw clear conclusions when the molecules are completely different on several levels. Here the adsorption process of a model protein, the hen egg-white lysozyme, and the same protein that underwent a thermal treatment in the dry state, was characterized. The consequences of this treatment have been previously studied: net charge and hydrophobicity increase and lesser protein stability, but no secondary and tertiary structure modification (Desfougères, Y.; Jardin, J.; Lechevalier, V.; Pezennec, S.; Nau, F. Biomacromolecules 2011, 12, 156-166). The present study shows that these slight modifications dramatically increase the interfacial properties of the protein, since the adsorption to the air-water interface is much faster and more efficient (higher surface pressure). Moreover, a thick and strongly viscoelastic multilayer film is created, while native lysozyme adsorbs in a fragile monolayer film. Another striking result is that completely different behaviors were observed between two molecular species, i.e., native and native-like lysozyme, even though these species could not be distinguished by usual spectroscopic methods. This suggests that the air-water interface could be considered as a useful tool to reveal very subtle differences between protein molecules.
Collapse
|
31
|
Mikhailovskaya AA, Noskov BA, Lin SY, Loglio G, Miller R. Formation of Protein/Surfactant Adsorption Layer at the Air/Water Interface as Studied by Dilational Surface Rheology. J Phys Chem B 2011; 115:9971-9. [DOI: 10.1021/jp204956g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. A. Mikhailovskaya
- Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia
| | - B. A. Noskov
- Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia
| | - S.-Y. Lin
- Chemical Engineering Department, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei, 106 Taiwan
| | - G. Loglio
- Dipartimento di Chimica Organica, Universita degli Studi di Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - R. Miller
- MPI für Kolloid- und Grenzflächenforschung, Wissenschaftspark Golm, D-14424 Golm, Germany
| |
Collapse
|
32
|
Wang KH, Syu MJ, Chang CH, Lee YL. Headgroup effects of template monolayers on the adsorption behavior and conformation of glucose oxidase adsorbed at air/liquid interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:7595-7602. [PMID: 21608978 DOI: 10.1021/la201496j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Stearic acid (SA) and octadecylamine (ODA) monolayers at the air/liquid interface were used as template layers to adsorb glucose oxidase (GOx) from aqueous solution. The effect of the template monolayers on the adsorption behavior of GOx was studied in terms of the variation of surface pressure, the evolution of surface morphology observed by BAM and AFM, and the conformation of adsorbed GOx. The results show that the presence of a template monolayer can enhance the adsorption rate of GOx; furthermore, ODA has a higher ability, compared to SA, to adsorb GOx, which is attributed to the electrostatic attractive interaction between ODA and GOx. For adsorption performed on a bare surface or on an SA monolayer, the surface pressure approaches an equilibrium value (ca. 8 mN/m) after 2 to 3 h of adsorption and remains nearly constant in the following adsorption process. For the adsorption on an ODA monolayer, the surface pressure will increase further 1 to 2 h after approaching the first equilibrium pressure, which is termed the second adsorption stage. The measurement of circular dichroism (CD) spectroscopy indicates that the Langmuir-Blodgett films of adsorbed GOx transferred at the first equilibrium state (π = 8 mN/m) have mainly a β-sheet conformation, which is independent of the type of template monolayers. However, the ODA/GOx LB film transferred at the second adsorption stage has mainly an α-helix conformation. It is concluded that the specific interaction between ODA and GOx not only leads to a higher adsorption rate and adsorbed amount of GOx but also induces a conformation change in adsorbed GOx from β-sheet to α-helix. The present results indicate that is possible to control the conformation of adsorbed protein by selecting the appropriate template monolayer.
Collapse
Affiliation(s)
- Ke-Hsuan Wang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | | | | | | |
Collapse
|
33
|
Sivaraman B, Latour RA. Delineating the roles of the GPIIb/IIIa and GP-Ib-IX-V platelet receptors in mediating platelet adhesion to adsorbed fibrinogen and albumin. Biomaterials 2011; 32:5365-70. [PMID: 21529934 DOI: 10.1016/j.biomaterials.2011.04.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 04/05/2011] [Indexed: 11/16/2022]
Abstract
Platelet adhesion to adsorbed plasma proteins, such as fibrinogen (Fg), has been conventionally thought to be mediated by the GPIIb/IIIa receptor binding to Arg-Gly-Asp (RGD)-like motifs in the adsorbed protein. In previous studies, we showed that platelet adhesion response to adsorbed Fg and Alb was strongly influenced by the degree of adsorption-induced protein unfolding and that platelet adhesion was only partially blocked by soluble RGD, with RGD-blocked platelets adhering without activation. Based on these results, we hypothesized that in addition to the RGD-specific GPIIb/IIIa receptor, which mediates both adhesion and activation, a non-RGD-specific receptor set likely also plays a role in platelet adhesion (but not activation) to both Fg and albumin (Alb). To identify and elucidate the role of these receptors, in addition to GPIIb/IIIa, we also examined the GPIb-IX-V receptor complex, which has been shown to mediate platelet adhesion (but not activation) in studies by other groups. The platelet suspension was pretreated with either a GPIIb/IIIa-antagonist drug Aggrastat(®) or monoclonal antibodies 6B4 or 24G10 against GPIb-IX-V prior to adhesion on Fg- and Alb-coated OH- and CH(3)-functionalized alkanethiol self-assembled monolayer surfaces. The results revealed that GPIIb/IIIa is the primary receptor set involved in platelet adhesion to adsorbed Fg and Alb irrespective of their degree of adsorption-induced unfolding, while the GPIb-IX-V receptor complex plays an insignificant role. Overall, these studies provide novel insights into the molecular-level mechanisms mediating platelet interactions with adsorbed plasma proteins, thereby assisting the biomaterials field develop potent strategies for inhibiting platelet-protein interactions in the design of more hemocompatible cardiovascular biomaterials and effective anti-thrombotic therapies.
Collapse
Affiliation(s)
- Balakrishnan Sivaraman
- Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, United States
| | | |
Collapse
|
34
|
Hassan N, Maldonado-Valderrama J, Gunning AP, Morris VJ, Ruso JM. Surface Characterization and AFM Imaging of Mixed Fibrinogen−Surfactant Films. J Phys Chem B 2011; 115:6304-11. [DOI: 10.1021/jp200835j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Natalia Hassan
- Soft Matter and Molecular Biophysics
Group, Department of Applied Physics University of Santiago de Compostela, Campus Sur s/n, 15782, Santiago de Compostela,
Spain
| | | | - A. Patrick Gunning
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, U.K
| | - Victor J. Morris
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, U.K
| | - Juan M. Ruso
- Soft Matter and Molecular Biophysics
Group, Department of Applied Physics University of Santiago de Compostela, Campus Sur s/n, 15782, Santiago de Compostela,
Spain
| |
Collapse
|
35
|
Noskov BA, Mikhailovskaya AA, Lin SY, Loglio G, Miller R. Bovine serum albumin unfolding at the air/water interface as studied by dilational surface rheology. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:17225-17231. [PMID: 20961051 DOI: 10.1021/la103360h] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Measurements of the surface dilational elasticity close to equilibrium did not indicate significant distinctions in the surface conformation of different forms of bovine serum albumin (BSA) in a broad pH range. At the same time, the protein denaturation in the surface layer under the influence of guanidine hydrochloride led to strong changes in the kinetic dependencies of the dynamic surface elasticity if the denaturant concentration exceeded a critical value. It was shown that the BSA unfolding at the solution surface occurred at lower denaturant concentrations than in the bulk phase. In the former case, the unfolding resulted in the formation of loops and tails at surface pressures above 12 mN/m. The maximal values of the dynamic surface elasticity almost coincided with the corresponding data for the recently investigated solutions of β-lactoglobulin, thereby indicating a similar unfolding mechanism.
Collapse
Affiliation(s)
- B A Noskov
- Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia
| | | | | | | | | |
Collapse
|
36
|
|
37
|
Jutz G, Böker A. Bio-inorganic microcapsules from templating protein- and bionanoparticle-stabilized Pickering emulsions. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b925018b] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
38
|
Sivaraman B, Latour RA. The adherence of platelets to adsorbed albumin by receptor-mediated recognition of binding sites exposed by adsorption-induced unfolding. Biomaterials 2009; 31:1036-44. [PMID: 19864017 DOI: 10.1016/j.biomaterials.2009.10.017] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 10/08/2009] [Indexed: 11/27/2022]
Abstract
Although albumin (Alb) is the most abundant plasma protein, it is considered to be non-adhesive to platelets, as it lacks any known amino acid sequences for binding platelet receptors. Recent studies have suggested that platelets adhere to adsorbed Alb by mechanisms linked to its conformational state. To definitively address this issue we used circular dichroism (CD) spectropolarimetry to characterize the conformation of Alb adsorbed on a broad range of surface chemistries from a wide range of Alb solution concentrations, with platelet adhesion examined using a lactate dehydrogenase (LDH) assay and scanning electron microscopy (SEM). Our results prove that platelets bind to adsorbed Alb through receptor-mediated processes, with binding sites in Alb exposed and/or formed by adsorption-induced protein unfolding. Most importantly, beyond a critical degree of unfolding, the platelet adhesion levels correlated strongly with the adsorption-induced unfolding in Alb. The blockage of Arg-Gly-Asp (RGD) specific platelet receptors using an Arg-Gly-Asp-Ser (RGDS) peptide led to significant inhibition of platelet adhesion to adsorbed Alb, with the extent of inhibition and morphology of adherent platelets being similar for both Alb and Fg. Chemical neutralization of arginine (Arg) residues in the adsorbed Alb layer inhibited platelet-Alb interactions significantly, indicating that Arg residues play a prominent role in mediating platelet adhesion to Alb. These results provide deeper insight into the molecular mechanisms that mediate the interactions of platelets with adsorbed proteins, and how to control these interactions to improve the blood compatibility of biomaterials for cardiovascular applications.
Collapse
Affiliation(s)
- Balakrishnan Sivaraman
- Department of Bioengineering, 501 Rhodes Engineering Center, Clemson University, Clemson, SC 29634, USA
| | | |
Collapse
|
39
|
Noskov BA, Grigoriev DO, Latnikova AV, Lin SY, Loglio G, Miller R. Impact of Globule Unfolding on Dilational Viscoelasticity of β-Lactoglobulin Adsorption Layers. J Phys Chem B 2009; 113:13398-404. [DOI: 10.1021/jp905413q] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. A. Noskov
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia, MPI für Kolloid- und Grenzflächenforschung, Forschungcampus Golm, D14476 Golm, Germany, National Taiwan University of Science and Technology, Chemical Engineering Department, 43 Keelung Road, Section 4, Taipei, 106 Taiwan, and Universita degli Studi di Firenze, Dipartimento di Chimica Organica, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - D. O. Grigoriev
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia, MPI für Kolloid- und Grenzflächenforschung, Forschungcampus Golm, D14476 Golm, Germany, National Taiwan University of Science and Technology, Chemical Engineering Department, 43 Keelung Road, Section 4, Taipei, 106 Taiwan, and Universita degli Studi di Firenze, Dipartimento di Chimica Organica, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - A. V. Latnikova
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia, MPI für Kolloid- und Grenzflächenforschung, Forschungcampus Golm, D14476 Golm, Germany, National Taiwan University of Science and Technology, Chemical Engineering Department, 43 Keelung Road, Section 4, Taipei, 106 Taiwan, and Universita degli Studi di Firenze, Dipartimento di Chimica Organica, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - S.-Y. Lin
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia, MPI für Kolloid- und Grenzflächenforschung, Forschungcampus Golm, D14476 Golm, Germany, National Taiwan University of Science and Technology, Chemical Engineering Department, 43 Keelung Road, Section 4, Taipei, 106 Taiwan, and Universita degli Studi di Firenze, Dipartimento di Chimica Organica, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - G. Loglio
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia, MPI für Kolloid- und Grenzflächenforschung, Forschungcampus Golm, D14476 Golm, Germany, National Taiwan University of Science and Technology, Chemical Engineering Department, 43 Keelung Road, Section 4, Taipei, 106 Taiwan, and Universita degli Studi di Firenze, Dipartimento di Chimica Organica, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - R. Miller
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia, MPI für Kolloid- und Grenzflächenforschung, Forschungcampus Golm, D14476 Golm, Germany, National Taiwan University of Science and Technology, Chemical Engineering Department, 43 Keelung Road, Section 4, Taipei, 106 Taiwan, and Universita degli Studi di Firenze, Dipartimento di Chimica Organica, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| |
Collapse
|
40
|
The stability of the archaeal HU histone-like DNA-binding protein from Thermoplasma volcanium. Extremophiles 2008; 13:1-10. [PMID: 18818867 DOI: 10.1007/s00792-008-0190-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2008] [Accepted: 09/01/2008] [Indexed: 10/21/2022]
Abstract
The complete genome analysis of the archaeon Thermoplasma volcanium has revealed a gene assigned to encode the histone-like DNA-binding protein HU. Thermoplasma volcanium is a moderate thermophile growing around 60 degrees C and it is adaptable to aerobic and anaerobic environment and therefore it is unique as a candidate for the origin of eukaryotic nuclei in the endosymbiosis hypothesis. The HU protein is the major component of the bacterial nuclei and therefore it is an important protein to be studied. The gene for HUTvo protein (huptvo) was cloned from the genomic DNA of T. volcanium and overexpressed in Escherichia coli. A fast and efficient purification scheme was established to produce an adequate amount of bioactive protein for biochemical and biophysical studies. Highly purified HUTvo was studied for its DNA-binding activity and thermostability. As studied by circular dichroism and high-precision differential scanning microcalorimetry, the thermal unfolding of HUTvo protein is reversible and can be well described by a two-state model with dissociation of the native dimeric state into denatured monomers. The G versus T profile for HUTvo compared to the hyperthermophilic marine eubacterial counterpart from Thermotoga maritima, HUTmar, clearly shows that the archaeal protein has adopted a less efficient molecular mechanism to cope with high temperature. The molecular basis of this phenomenon is discussed.
Collapse
|
41
|
Soman P, Rice Z, Siedlecki CA. Measuring the time-dependent functional activity of adsorbed fibrinogen by atomic force microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8801-8806. [PMID: 18616311 DOI: 10.1021/la801227e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In this work, we measured time-dependent functional changes in adsorbed fibrinogen by measuring antigen-antibody debonding forces with atomic force microscopy (AFM). AFM probes were functionalized with monoclonal antibodies recognizing fibrinogen gamma 392-411, which includes the platelet binding dodecapeptide region. These probes were used to collect force measurements between the antibody and fibrinogen on mica substrates and the probability of antigen recognition was calculated. Statistical analysis showed that the probability of antibody-antigen recognition peaked at approximately 45 min postadsorption and decreased with increasing residence time. Macroscale platelet adhesion measurements on these mica substrates were determined to be greatest at fibrinogen residence times of approximately 45 min, which correlated well with the functional activity of adsorbed fibrinogen as measured by the modified AFM probes. These results demonstrate the utility of this approach for measuring protein function at or near the molecular scale and offers new opportunities for improved insights into the molecular basis for the biological response to biomaterials.
Collapse
Affiliation(s)
- Pranav Soman
- Department of Bioengineering and Surgery, The Pennsylvania State University College of Medicine, Hershey Pennsylvania 17033, USA
| | | | | |
Collapse
|
42
|
Mansour HM, Damodaran S, Zografi G. Characterization of the in situ structural and interfacial properties of the cationic hydrophobic heteropolypeptide, KL4, in lung surfactant bilayer and monolayer models at the air-water interface: implications for pulmonary surfactant delivery. Mol Pharm 2008; 5:681-95. [PMID: 18630875 DOI: 10.1021/mp700123p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study examines the various equilibrium in situ secondary structures of the pharmaceutical heteropolypeptide, KL 4, in the solid state, in solution, and in the monolayer state alone and mixed with dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleoylphosphatidylglycerol (POPG). In situ surface circular dichroism spectroscopy, using a method first reported by Damodaran (Damodaran, S. Anal. Bioanal. Chem. 2003, 376, 182-188), of equilibrated KL 4, DPPC/KL 4, POPG/KL 4, and DPPC/POPG/KL 4 monolayers at the air-water interface was used to examine the in situ two-dimensional conformation of KL 4. Gravimetric vapor sorption by solid KL 4 was used to analyze the effects of water molecules on the conformation of KL 4 when confined as a monolayer at the surface of water. Solid-state KL 4 conformation was determined by X-ray powder diffraction (XRPD). The equilibrium interfacial and spreading properties were measured at 25 degrees C, 37 degrees C, and 45 degrees C using the Wilhelmy plate method and Langmuir film balance. Equilibrium phase transition temperatures were measured using differential scanning calorimetry (DSC). It was found that solid-state KL 4, which takes up very little water, exhibits beta-sheet and alpha-helix secondary structures, whereas KL 4 in solution appears to exist only as an alpha-helix. KL 4 forms a stable, insoluble monolayer, exhibiting beta-sheet and aperiodic structures. These structures provide KL 4, when confined in two-dimensions, the structural flexibility to maximize favorable cationic lysine-water interactions and favorable leucine-leucine hydrophobic and van der Waals interactions; while effectively "shielding" the leucine residues away from water. In DPPC/KL 4 monolayers, KL 4 retains its native beta-sheet and aperiodic structures, consistent with phase separation of DPPC and KL 4 in bilayers and monolayers. In POPG/KL 4 monolayers, KL 4 exhibits an increase in aperiodic secondary structures (loss of beta-sheet) to maximize favorable electrostatic interactions, consistent with the observed negative deviations from ideal monolayer mixing.
Collapse
Affiliation(s)
- Heidi M Mansour
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
| | | | | |
Collapse
|
43
|
Beaufils S, Hadaoui-Hammoutène R, Vié V, Miranda G, Perez J, Terriac E, Henry G, Delage MM, Léonil J, Martin P, Renault A. Comparative behaviour of goat β and αs1-caseins at the air–water interface and in solution. Food Hydrocoll 2007. [DOI: 10.1016/j.foodhyd.2006.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
44
|
Vessely CR, Carpenter JF, Schwartz DK. Calcium-Induced Changes to the Molecular Conformation and Aggregate Structure of β-Casein at the Air−Water Interface. Biomacromolecules 2005; 6:3334-44. [PMID: 16283763 DOI: 10.1021/bm050353w] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The influence of calcium on interactions of beta-casein at the air-water interface has been studied by several techniques, including interfacial rheology, atomic force microscopy (AFM), infrared reflectance-absorbance spectroscopy (IRRAS), and zeta potential measurements. In the absence of calcium, a weak interfacial gel forms after about 2.5 h. Also in the absence of calcium, the adsorbed beta-casein film exhibits some degree of both intra- and intermolecular structural organization. For example, IRRAS spectra show a measurable amount of alpha-helix content, and AFM images indicate the presence of interfacial aggregates with a characteristic lateral length scale of 20-30 nm, which we interpret as hemimicelles. Upon the addition of calcium, particularly at Ca:beta-casein molar ratios above approximately 5:1, a stronger interfacial gel forms more quickly; for example, the interfacial shear moduli increase twice as rapidly. Also under these conditions (5:1 Ca:beta-casein ratio) there is little evidence of structural organization; i.e., the alpha-helix peaks are very weak, and AFM images show a disordered, but continuous film, without distinct hemimicelles. On the basis of these findings, we hypothesize that calcium binding destabilizes the coupled intra- and intermolecular structural organization, and that the loss of organization permits more rapid interfacial gelation. These phenomena are characteristic of the air-water interface; they are not accompanied by analogous structural changes in bulk solution.
Collapse
Affiliation(s)
- Christina R Vessely
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | | | | |
Collapse
|
45
|
Maldonado-Valderrama J, Fainerman VB, Aksenenko E, Jose Gálvez-Ruiz M, Cabrerizo-Vílchez MA, Miller R. Dynamics of protein adsorption at the oil–water interface: comparison with a theoretical model. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2004.10.131] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
46
|
Lin SY, Wei YS, Hsieh TF, Li MJ. Pressure dependence of human fibrinogen correlated to the conformational ?-helix to ?-sheet transition: An Fourier transform infrared study microspectroscopic study. Biopolymers 2004; 75:393-402. [PMID: 15457437 DOI: 10.1002/bip.20012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We used Fourier transform infrared (FTIR) microspectroscopy to investigate pressure-induced conformational changes in secondary structure of fibrinogen (FBG). Solid state FBG was compressed on a KBr pellet (1KBr method) or between two KBr pellets (2KBr method). The peak positions of the original and second-derivative ir spectra of compressed FBG samples prepared by the 1KBr method were similar to FBG sample without pressure. When FBG was prepared by the 2KBr method and pressure was increased up to 400 kg/cm(2), peaks at 1625 (intermolecular beta-sheet) and 1611 (beta-sheet aggregates structure and/or the side-chain absorption of the tyrosine residues) cm(-1) were enhanced. The peaks near 1661 (beta-sheet) and 1652 (alpha-helix) cm(-1) also exhibited a marked change with pressure. A linear correlation was found between the peak intensity ratio of 1611/1652 cm(-1) (r = 0.9879) or 1625/1652 cm(-1) (r = 0.9752) and applied pressure. The curve-fitted compositional changes in secondary structure of FBG also indicate that the composition of the alpha-helix structure (1657-1659 cm(-1)) was gradually reduced with the increase in compression pressure, but the composition of the beta-sheet structure (1681, 1629, and 1609 cm(-1)) gradually increased. This indicates that pressure-induced conformational changes in FBG include not only transformations from alpha-helix to beta-sheet structure, but also unfolding and denaturation of FBG and the formation of aggregates.
Collapse
Affiliation(s)
- Shan-Yang Lin
- Biopharmaceutics Laboratory, Department of Medical Research and Education, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China.
| | | | | | | |
Collapse
|