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Fossum CJ, Johnson BOV, Golde ST, Kielman AJ, Finke B, Smith MA, Lowater HR, Laatsch BF, Bhattacharyya S, Hati S. Insights into the Mechanism of Tryptophan Fluorescence Quenching due to Synthetic Crowding Agents: A Combined Experimental and Computational Study. ACS OMEGA 2023; 8:44820-44830. [PMID: 38046287 PMCID: PMC10688029 DOI: 10.1021/acsomega.3c06006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/28/2023] [Accepted: 10/31/2023] [Indexed: 12/05/2023]
Abstract
Intrinsic tryptophan fluorescence spectroscopy is an important tool for examining the effects of molecular crowding and confinement on the structure, dynamics, and function of proteins. Synthetic crowders such as dextran, ficoll, polyethylene glycols, polyvinylpyrrolidone, and their respective monomers are used to mimic crowded intracellular environments. Interactions of these synthetic crowders with tryptophan and the subsequent impact on its fluorescence properties are therefore critically important for understanding the possible interference created by these crowders. In the present study, the effects of polymer and monomer crowders on tryptophan fluorescence were assessed by using experimental and computational approaches. The results of this study demonstrated that both polymer and monomer crowders have an impact on the tryptophan fluorescence intensity; however, the molecular mechanisms of quenching were different. Using Stern-Volmer plots and a temperature variation study, a physical basis for the quenching mechanism of commonly used synthetic crowders was established. The quenching of free tryptophan was found to involve static, dynamic, and sphere-of-action mechanisms. In parallel, computational studies employing Kohn-Sham density functional theory provided a deeper insight into the effects of intermolecular interactions and solvation, resulting in differing quenching modes for these crowders. Taken together, the study offers new physical insights into the quenching mechanisms of some commonly used monomer and polymer synthetic crowders.
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Affiliation(s)
| | - Benjamin O. V. Johnson
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Spencer T. Golde
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Alexis J. Kielman
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Brianna Finke
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Macey A. Smith
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Harrison R. Lowater
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Bethany F. Laatsch
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Sudeep Bhattacharyya
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
| | - Sanchita Hati
- Department of Chemistry and
Biochemistry, University of Wisconsin-Eau
Claire, Eau Claire, Wisconsin 54701, United States
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Lueckheide M, Marin A, Tagad HD, Posey ND, Prabhu VM, Andrianov AK. Monitoring Protein Complexation with Polyphosphazene Polyelectrolyte Using Automated Dynamic Light Scattering Titration and Asymmetric Flow Field Flow Fractionation and Protein Recognition Immunoassay. ACS POLYMERS AU 2023; 3:354-364. [PMID: 37841951 PMCID: PMC10571102 DOI: 10.1021/acspolymersau.3c00006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/31/2023] [Accepted: 04/05/2023] [Indexed: 10/17/2023]
Abstract
Polyphosphazenes represent a class of intrinsically flexible polyelectrolytes with potent immunoadjuvant activity, which is enabled through non-covalent self-assembly with antigenic proteins by charge complexation. The formation of supramolecular complexes between polyphosphazene adjuvant, poly[di(carboxylatophenoxy)phosphazene] (PCPP), and a model vaccine antigen, hen egg lysozyme, was studied under physiological conditions using automated dynamic light scattering titration, asymmetric flow field flow fractionation (AF4), enzyme-linked immunosorbent assay (ELISA), and fluorescent quenching methods. Three regimes of self-assembly were observed covering complexation of PCPP with lysozyme in the nano-scale range, multi-chain complexes, and larger aggregates with complexes characterized by a maximum loading of over six hundred protein molecules per PCPP chain and dissociation constant in the micromolar range (Kd = 7 × 10-6 mol/L). The antigenicity of PCPP bound lysozyme, when compared to equivalent lysozyme solutions, was largely retained for all complexes, but observed a dramatic reduction for heavily aggregated systems. Routes to control the complexation regimes with elevated NaCl or KCl salt concentrations indicate ion-specific effects, such that more smaller-size complexes are present at higher NaCl, counterintuitive with respect to PCPP solubility arguments. While the order of mixing shows a prominent effect at lower stoichiometries of mixing, higher NaCl salt reduces the effect all together.
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Affiliation(s)
- Michael Lueckheide
- Materials
Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Alexander Marin
- Institute
for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Harichandra D. Tagad
- Institute
for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Nicholas D. Posey
- Materials
Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Vivek M. Prabhu
- Materials
Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Alexander K. Andrianov
- Institute
for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
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3
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Tagad HD, Marin A, Wang R, Yunus AS, Fuerst TR, Andrianov AK. Fluorine-Functionalized Polyphosphazene Immunoadjuvant: Synthesis, Solution Behavior and In Vivo Potency. Molecules 2023; 28:4218. [PMID: 37241958 PMCID: PMC10221343 DOI: 10.3390/molecules28104218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 05/28/2023] Open
Abstract
The inclusion of fluorine motifs in drugs and drug delivery systems is an established tool for modulating their biological potency. Fluorination can improve drug specificity or boost the vehicle's ability to cross cellular membranes. However, the approach has yet to be applied to vaccine adjuvants. Herein, the synthesis of fluorinated bioisostere of a clinical stage immunoadjuvant-poly[di(carboxylatophenoxy)phosphazene], PCPP-is reported. The structure of water-soluble fluoropolymer-PCPP-F, which contains two fluorine atoms per repeat unit-was confirmed using 1H, 31P and 19F NMR, and its molecular mass and molecular dimensions were determined using size-exclusion chromatography and dynamic light scattering. Insertion of fluorine atoms in the polymer side group resulted in an improved solubility in acidic solutions and faster hydrolytic degradation rate, while the ability to self-assemble with an antigenic protein, lysozyme-an important feature of polyphosphazene vaccine adjuvants-was preserved. In vivo assessment of PCPP-F demonstrated its greater ability to induce antibody responses to Hepatitis C virus antigen when compared to its non-fluorinated counterpart. Taken together, the superior immunoadjuvant activity of PCPP-F, along with its improved formulation characteristics, demonstrate advantages of the fluorination approach for the development of this family of macromolecular vaccine adjuvants.
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Affiliation(s)
- Harichandra D. Tagad
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Alexander Marin
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Ruixue Wang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Abdul S. Yunus
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Thomas R. Fuerst
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Alexander K. Andrianov
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
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4
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Mondal S, Das S, Swamy MJ. Macromolecular Crowding Significantly Affects the Conformational Features and Carbohydrate Binding Properties of CIA17, a PP2-Type Lectin from Coccinia indica. Biochemistry 2022; 61:2344-2357. [PMID: 36200563 DOI: 10.1021/acs.biochem.2c00389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of macromolecular crowding on the conformational features and carbohydrate binding properties of CIA17, a PP2-type lectin, was investigated employing polymeric dextrans D6, D40, and D70 (Mr ∼ 6, 40, and 70 kDa, respectively) as crowders. While the secondary structure of CIA17 was significantly affected by D6, with a considerable decrease in the number of β-sheets and β-turns with a corresponding increase in the number of unordered structures, relatively smaller changes were induced by D40 and D70. However, differential scanning calorimetry (DSC) studies revealed that the thermal stability of the protein remains unchanged in the presence of crowders. While the larger dextrans, D70 and D40, induced modest quenching (∼10%) of the protein fluorescence by a static pathway, the smaller D6 induced a higher degree of quenching (37%), which involved both static and collisional quenching processes. The results of fluorescence correlation spectroscopy measurements together with DSC studies suggested that CIA17 forms larger oligomers in the presence of D40 and D70 but D6 prevents the formation of higher-order oligomers. The association constant for the CIA17-chitooligosaccharide interaction increased by ∼30% and 160% in the presence of D40 and D70, respectively, but decreased by ∼30% in the presence of D6. The higher binding affinity can be attributed to the excluded volume effect, i.e., an increased effective concentration of the protein in the presence of D40 and D70, whereas D6, being smaller, possibly penetrates into the protein interior, disrupting the water structure around the protein and also inducing conformational changes, resulting in weaker binding. These observations demonstrate that molecular crowding significantly affects the carbohydrate binding characteristics of lectins, which can modulate their physiological function.
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Affiliation(s)
- Saradamoni Mondal
- School of Chemistry, University of Hyderabad, Hyderabad500 046, India
| | - Somnath Das
- School of Chemistry, University of Hyderabad, Hyderabad500 046, India
| | - Musti J Swamy
- School of Chemistry, University of Hyderabad, Hyderabad500 046, India
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Oliva R, Niccoli M, Castronuovo G. Binding and Stability Properties of PEG2000 to Globular Proteins: the Case of Lysozyme. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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6
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Meena P, Kishore N. Ionic strength modulated interactions of sorbitol with lysozyme and amino acids: Quantitative understanding in protein stabilizing effects. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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7
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Rasteniene A, Gruskiene R, Sereikaite J. Interaction of ectoine and hydroxyectoine with protein: fluorescence study. CHEMICAL PAPERS 2021. [DOI: 10.1007/s11696-021-01527-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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Karmakar S, Chakraborty S, Gautam S, Chowdhury PK. Exploring the potency of the naturally occurring polyphenol curcumin as a probe for protein aggregation in crowded environments. Int J Biol Macromol 2019; 141:1088-1101. [DOI: 10.1016/j.ijbiomac.2019.09.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 01/12/2023]
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9
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Samanta N, Das Mahanta D, Patra A, Mitra RK. Soft interaction and excluded volume effect compete as polyethylene glycols modulate enzyme activity. Int J Biol Macromol 2018; 118:209-215. [PMID: 29920368 DOI: 10.1016/j.ijbiomac.2018.06.073] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 10/28/2022]
Abstract
Polyethylene glycols (PEGs) can either preferentially bind to biomolecules or exert excluded volume effect depending upon their chain length and concentration. We have studied the effect of ethylene glycol (EG) and PEGs of different chain lengths (Mn 400 and 4000) on the enzyme efficiency of hen-egg-white lysozyme (HEWL) on Micrococcus lysodeikticus (M. Lys.) cell. The activity shows a bell-like profile as the turnover number increases from ~1.3 × 105 s-1 M-1 in water to ~1.7 × 105 s-1 M-1 in presence of 2% PEG-400 beyond which it decreases to ~0.7 × 105 s-1 M-1 at 20% PEG-400. Solvent polarity, excluded volume effect, soft nonspecific interactions and structural flexibility are found to be the competing factors which govern the overall enzyme activity as evidenced from circular dichroism (CD) and fluorescence measurements. Thermal unfolding temperature (Tm) of HEWL also shows a bell-shaped profile with PEG concentration which establishes possible correlation with its activity. We also observe a minimum in the activation energy barrier for the catalysis at low osmolyte concentrations. The maximum in the enzyme efficiency has been explained on the basis of an optimization between excluded volume effect and soft interaction among the protein and the cosolutes.
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Affiliation(s)
- Nirnay Samanta
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake Kolkata 700106, India.
| | - Debasish Das Mahanta
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake Kolkata 700106, India
| | - Animesh Patra
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake Kolkata 700106, India
| | - Rajib Kumar Mitra
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake Kolkata 700106, India.
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10
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Wang Z, Lu HP. Single-Molecule Spectroscopy Study of Crowding-Induced Protein Spontaneous Denature and Crowding-Perturbed Unfolding–Folding Conformational Fluctuation Dynamics. J Phys Chem B 2018; 122:6724-6732. [DOI: 10.1021/acs.jpcb.8b03119] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Zijiang Wang
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - H. Peter Lu
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
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11
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Behavior of bovine serum albumin in the presence of locust bean gum. Int J Biol Macromol 2018; 111:1-10. [DOI: 10.1016/j.ijbiomac.2017.12.139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/23/2017] [Accepted: 12/25/2017] [Indexed: 12/16/2022]
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12
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Crowded milieu tuning the stability and activity of stem bromelain. Int J Biol Macromol 2018; 109:114-123. [DOI: 10.1016/j.ijbiomac.2017.12.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/06/2017] [Accepted: 12/08/2017] [Indexed: 11/24/2022]
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13
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van Wilderen LJGW, Brunst H, Gustmann H, Wachtveitl J, Broos J, Bredenbeck J. Cyano-tryptophans as dual infrared and fluorescence spectroscopic labels to assess structural dynamics in proteins. Phys Chem Chem Phys 2018; 20:19906-19915. [DOI: 10.1039/c8cp00846a] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
By moving the cyano group position on the indole ring, both artificial amino acids report differently to their microscopic environment.
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Affiliation(s)
| | - H. Brunst
- Institute of Biophysics
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
| | - H. Gustmann
- Institute of Physical and Theoretical Chemistry
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
| | - J. Wachtveitl
- Institute of Physical and Theoretical Chemistry
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
| | - J. Broos
- Laboratory of Biophysical Chemistry and GBB (Groningen Biomolecular Science and Biotechnology Institute)
- University of Groningen
- 9747 AG Groningen
- The Netherlands
| | - J. Bredenbeck
- Institute of Biophysics
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
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