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Stachurska K, Marcisz U, Długosz M, Antosiewicz JM. Kinetics of Structural Transitions Induced by Sodium Dodecyl Sulfate in α-Chymotrypsin. ACS OMEGA 2023; 8:49137-49149. [PMID: 38162786 PMCID: PMC10753550 DOI: 10.1021/acsomega.3c07256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/16/2023] [Accepted: 11/23/2023] [Indexed: 01/03/2024]
Abstract
The temporal changes in circular dichroism at 222 and 260 nm were recorded by using stopped-flow spectroscopy after mixing α-chymotrypsin solutions with sodium dodecyl sulfate solutions. Simultaneously with the circular dichroism signal, the fluorescence emission was recorded. Changes in the secondary and tertiary structures of chymotrypsin induced by sodium dodecyl sulfate are characterized by either three or four one-way reactions with relaxation amplitudes and times precisely determined by an advanced numerical procedure of Kuzmič. Quantitatively, transitions within the secondary and tertiary structures of the protein are significantly different. Moreover, changes in the tertiary structure depend on the type of recorded signal (either circular dichroism or fluorescence) and the wavelength of the incident radiation. The latter observation is particularly interesting as it indicates that the contributions of protein's different tryptophans to the total recorded fluorescence depend on the excitation wavelength. We present several results justifying this hypothesis.
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Affiliation(s)
- Karolina Stachurska
- Biophysics Division, Institute of Experimental
Physics, Faculty of Physics, University
of Warsaw, Pasteura 5 Street, 02-093 Warsaw, Poland
| | - Urszula Marcisz
- Biophysics Division, Institute of Experimental
Physics, Faculty of Physics, University
of Warsaw, Pasteura 5 Street, 02-093 Warsaw, Poland
| | - Maciej Długosz
- Biophysics Division, Institute of Experimental
Physics, Faculty of Physics, University
of Warsaw, Pasteura 5 Street, 02-093 Warsaw, Poland
| | - Jan M. Antosiewicz
- Biophysics Division, Institute of Experimental
Physics, Faculty of Physics, University
of Warsaw, Pasteura 5 Street, 02-093 Warsaw, Poland
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2
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Shehata M, Ünlü A, Iglesias-Fernández J, Osuna S, Sezerman OU, Timucin E. Brave new surfactant world revisited by thermoalkalophilic lipases: computational insights into the role of SDS as a substrate analog. Phys Chem Chem Phys 2023; 25:2234-2247. [PMID: 36594810 DOI: 10.1039/d2cp05093e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Non-ionic surfactants were shown to stabilize the active conformation of thermoalkalophilic lipases by mimicking the lipid substrate while the catalytic interactions formed by anionic surfactants have not been well characterized. In this study, we combined μs-scale molecular dynamics (MD) simulations and lipase activity assays to analyze the effect of ionic surfactant, sodium dodecyl sulfate (SDS), on the structure and activity of thermoalkalophilic lipases. Both the open and closed lipase conformations that differ in geometry were recruited to the MD analysis to provide a broader understanding of the molecular effect of SDS on the lipase structure. Simulations at 298 K showed the potential of SDS for maintaining the active lipase through binding to the sn-1 acyl-chain binding pocket in the open conformation or transforming the closed conformation to an open-like state. Consistent with MD findings, experimental analysis showed increased lipase activity upon SDS incubation at ambient temperature. Notably, the lipase cores stayed intact throughout 2 μs regardless of an increase in the simulation temperature or SDS concentration. However, the surface structures were unfolded in the presence of SDS and at elevated temperature for both conformations. Simulations of the dimeric lipase were also carried out and showed reduced flexibility of the surface structures which were unfolded in the monomer, indicating the insulating role of dimer interactions against SDS. Taken together, this study provides insights into the possible substrate mimicry by the ionic surfactant SDS for the thermoalkalophilic lipases without temperature elevation, underscoring SDS's potential for interfacial activation at ambient temperatures.
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Affiliation(s)
- Mohamed Shehata
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem University, Istanbul 34752, Turkey.
| | - Aişe Ünlü
- Department of Chemistry, Gebze Technical University, Kocaeli, Turkey
| | | | - Sílvia Osuna
- CompBioLab Group, Institut de Química Computacional i Catàlisi (IQCC) and Department de Química, Universitat de Girona, c/Maria Aurèlia Capmany 69, 17003 Girona, Spain.,ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - O Ugur Sezerman
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem University, Istanbul 34752, Turkey.
| | - Emel Timucin
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem University, Istanbul 34752, Turkey.
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3
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Wei Y, Zhang J, Liu X. Surfactant-Assisted Assembly of Dipeptide Forming a Broom-like Structure. Molecules 2022; 27:molecules27154876. [PMID: 35956826 PMCID: PMC9369827 DOI: 10.3390/molecules27154876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
Understanding the influence of surfactants on the assembly of peptides has a considerable practical motivation. In this paper, we systematically study the anionic surfactant-assisted assembly of diphenylalanine (FF). FF forms broom-like structures in a concentration of sodium cholate (NaC) around the CMC, and assembles into linear and unidirectional rods in the presence of low and high surfactant concentrations. FF’s improved hydrogen bonding and controlled assembly rates are appropriate for other anionic surfactants. At this stage, the use of FF as the simplest protein consequence can be helpful in the investigation of further protein–surfactant interactions.
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4
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Stachurska K, Marcisz U, Długosz M, Antosiewicz JM. Circular Dichroism Spectra of α-Chymotrypsin-SDS Solutions Depend on the Procedure of Their Preparation. ACS OMEGA 2022; 7:23782-23789. [PMID: 35847307 PMCID: PMC9280762 DOI: 10.1021/acsomega.2c02438] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We recorded the far- and near-UV circular dichroism (CD) spectra of solutions of α-chymotrypsin and sodium dodecyl sulfate (SDS) with the final surfactant concentration significantly above the critical micellization concentration. Solutions were prepared using three different procedures. The reference procedure was to mix the chymotrypsin solution with the SDS solution once, immediately achieving the final SDS concentration. In alternative procedures, the protein solutions initially contained some SDS and were mixed with pure SDS solutions at a concentration to provide the same final surfactant as the reference mixing. We demonstrate that the supplementation to the selected final concentration of SDS of the pure chymotrypsin solution leads to different CD spectra than the supplementation to this final concentration of SDS in the chymotrypsin solution containing a small concentration of a few millimolar SDS. These differences disappear when the initial concentration of SDS in the protein solution, which we then supplement to the indicated final concentration, is higher. This suggests the irreversibility of the processes caused by the addition of SDS to chymotrypsin and the influence of the initial amount of this surfactant on the processes occurring with its further addition to the solution. For quantitative analysis of far-UV CD spectra in terms of populations of protein secondary structure elements, we used four well-established software packages. All programs consistently indicate that the observed differences in the far-UV CD spectra can be explained by the differences in the increase in the population of helical forms in chymotrypsin under the influence of SDS.
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Timmons PB, Hewage CM. Conformation and membrane interaction studies of the potent antimicrobial and anticancer peptide palustrin-Ca. Sci Rep 2021; 11:22468. [PMID: 34789753 PMCID: PMC8599514 DOI: 10.1038/s41598-021-01769-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 11/03/2021] [Indexed: 01/13/2023] Open
Abstract
Palustrin-Ca (GFLDIIKDTGKEFAVKILNNLKCKLAGGCPP) is a host defence peptide with potent antimicrobial and anticancer activities, first isolated from the skin of the American bullfrog Lithobates catesbeianus. The peptide is 31 amino acid residues long, cationic and amphipathic. Two-dimensional NMR spectroscopy was employed to characterise its three-dimensional structure in a 50/50% water/2,2,2-trifluoroethanol-\documentclass[12pt]{minimal}
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\begin{document}$$\alpha$$\end{document}α-helix that spans between Ile\documentclass[12pt]{minimal}
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\begin{document}$$^{6}$$\end{document}6-Ala\documentclass[12pt]{minimal}
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\begin{document}$$^{26}$$\end{document}26, and a cyclic disulfide-bridged domain at the C-terminal end of the peptide sequence, between residues 23 and 29. A molecular dynamics simulation was employed to model the peptide’s interactions with sodium dodecyl sulfate micelles, a widely used bacterial membrane-mimicking environment. Throughout the simulation, the peptide was found to maintain its \documentclass[12pt]{minimal}
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\begin{document}$$\alpha$$\end{document}α-helical conformation between residues Ile\documentclass[12pt]{minimal}
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\begin{document}$$^{26}$$\end{document}26, while adopting a position parallel to the surface to micelle, which is energetically-favourable due to many hydrophobic and electrostatic contacts with the micelle.
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Affiliation(s)
- Patrick B Timmons
- UCD School of Biomolecular and Biomedical Science, UCD Centre for Synthesis and Chemical Biology, UCD Conway Institute, University College Dublin, Dublin 4, Ireland.
| | - Chandralal M Hewage
- UCD School of Biomolecular and Biomedical Science, UCD Centre for Synthesis and Chemical Biology, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
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6
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Winogradoff D, John S, Aksimentiev A. Protein unfolding by SDS: the microscopic mechanisms and the properties of the SDS-protein assembly. NANOSCALE 2020; 12:5422-5434. [PMID: 32080694 PMCID: PMC7291819 DOI: 10.1039/c9nr09135a] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The effects of detergent sodium dodecyl sulfate (SDS) on protein structure and dynamics are fundamental to the most common laboratory technique used to separate proteins and determine their molecular weights: polyacrylamide gel electrophoresis. However, the mechanism by which SDS induces protein unfolding and the microstructure of protein-SDS complexes remain largely unknown. Here, we report a detailed account of SDS-induced unfolding of two proteins-I27 domain of titin and β-amylase-obtained through all-atom molecular dynamics simulations. Both proteins were found to spontaneously unfold in the presence of SDS at boiling water temperature on the time scale of several microseconds. The protein unfolding was found to occur via two distinct mechanisms in which specific interactions of individual SDS molecules disrupt the protein's secondary structure. In the final state of the unfolding process, the proteins are found to wrap around SDS micelles in a fluid necklace-and-beads configuration, where the number and location of bound micelles changes dynamically. The global conformation of the protein was found to correlate with the number of SDS micelles bound to it, whereas the number of SDS molecules directly bound to the protein was found to define the relaxation time scale of the unfolded protein. Our microscopic characterization of SDS-protein interactions sets the stage for future refinement of SDS-enabled protein characterization methods, including protein fingerprinting and sequencing using a solid-state nanopore.
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Affiliation(s)
- David Winogradoff
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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7
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Lopes-Rodrigues M, Matagne A, Zanuy D, Alemán C, Perpète EA, Michaux C. Structural and functional characterization of Solanum tuberosum VDAC36. Proteins 2019; 88:729-739. [PMID: 31833115 DOI: 10.1002/prot.25861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/26/2019] [Accepted: 12/06/2019] [Indexed: 11/05/2022]
Abstract
As it forms water-filled channel in the mitochondria outer membrane and diffuses essential metabolites such as NADH and ATP, the voltage-dependent anion channel (VDAC) protein family plays a central role in all eukaryotic cells. In comparison with their mammalian homologues, little is known about the structural and functional properties of plant VDACs. In the present contribution, one of the two VDACs isoforms of Solanum tuberosum, stVDAC36, has been successfully overexpressed and refolded by an in-house method, as demonstrated by the information on its secondary and tertiary structure gathered from circular dichroism and intrinsic fluorescence. Cross-linking and molecular modeling studies have evidenced the presence of dimers and tetramers, and they suggest the formation of an intermolecular disulfide bond between two stVDAC36 monomers. The pore-forming activity was also assessed by liposome swelling assays, indicating a typical pore diameter between 2.0 and 2.7 nm. Finally, insights about the ATP binding inside the pore are given by docking studies and electrostatic calculations.
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Affiliation(s)
- Maximilien Lopes-Rodrigues
- Laboratoire de Chimie Physique des Biomolécules, Unité de Chimie Physique Théorique et Structurale (UCPTS), University of Namur, Namur, Belgium.,Namur Institute of Structured Matter, University of Namur, Namur, Belgium.,Departament d'Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, Barcelona, Spain.,Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, Eduard Maristany, Barcelona, Spain
| | - André Matagne
- Laboratoire d'Enzymologie et Repliement des Protéines, Centre d'Ingénierie des Protéines (CIP), Université de Liège, Liège, Belgium
| | - David Zanuy
- Departament d'Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, Barcelona, Spain
| | - Carlos Alemán
- Departament d'Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, Barcelona, Spain.,Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, Eduard Maristany, Barcelona, Spain
| | - Eric A Perpète
- Laboratoire de Chimie Physique des Biomolécules, Unité de Chimie Physique Théorique et Structurale (UCPTS), University of Namur, Namur, Belgium.,Namur Institute of Structured Matter, University of Namur, Namur, Belgium.,Namur Research Institute for Life Sciences, University of Namur, Namur, Belgium
| | - Catherine Michaux
- Laboratoire de Chimie Physique des Biomolécules, Unité de Chimie Physique Théorique et Structurale (UCPTS), University of Namur, Namur, Belgium.,Namur Institute of Structured Matter, University of Namur, Namur, Belgium.,Institute of Life-Earth-Environment, University of Namur, Namur, Belgium
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8
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Advanced nanomedicine characterization by DLS and AF4-UV-MALS: Application to a HIV nanovaccine. J Pharm Biomed Anal 2019; 179:113017. [PMID: 31816470 DOI: 10.1016/j.jpba.2019.113017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/31/2019] [Accepted: 11/27/2019] [Indexed: 12/31/2022]
Abstract
Nanoformulations are complex systems where physicochemical properties determine their therapeutic efficacy and safety. In the case of nanovaccines, particle size and shape play a crucial role on the immune response generated. Furthermore, the antigen's integrity is also a key aspect to control when producing a nanovaccine. The determination of all those physicochemical properties is still an analytical challenge and the lack of well-established methods hinders the access of new therapeutics to the market. In this work, robust methods for the characterization of a novel HIV nanoparticle-based vaccine produced in good manufacturing practice (GMPs)-like environment were developed. With slightly polydisperse particles (< 0.2) close to 180 nm of size, batch-mode Dynamic Light Scattering (DLS) was validated to be used as a quality control technique in the pilot production plant. In addition, a high size resolution method using Asymmetrical Flow Field Flow Fractionation (AF4) demonstrated its ability to determine not only size and size distribution but also shape modification across the size and accurate quantification of the free active ingredient. Results showed a monomodal distribution of particles from 60 to 700 nm, most of them (> 90%) with size lower than 250 nm, consistent with more traditional techniques, and revealed a slight change in the structure of the particles induced by the presence of the antigen. Finally, a batch to batch variability lower than 20% was obtained by both DLS and AF4 methods indicating that preparation method was highly reproducible.
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9
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Li Y, Lee JS. Staring at protein-surfactant interactions: Fundamental approaches and comparative evaluation of their combinations - A review. Anal Chim Acta 2019; 1063:18-39. [DOI: 10.1016/j.aca.2019.02.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 02/07/2023]
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10
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Huda N, Hossain M, Bhuyan AK. Complete observation of all structural, conformational, and fibrillation transitions of monomeric globular proteins at submicellar sodium dodecyl sulfate concentrations. Biopolymers 2019; 110:e23255. [PMID: 30633322 DOI: 10.1002/bip.23255] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 11/06/2022]
Abstract
Although considerable information is available regarding protein-sodium dodecyl sulfate (SDS) interactions, it is still unclear as to how much SDS is needed to denature proteins. The role of protein charge and micellar surfactant concentration on amyloid fibrillation is also unclear. This study reports on equilibrium measurements of SDS interaction with six model proteins and analyzes the results to obtain a general understanding of conformational breakdown, reorganization and restructuring of secondary structure, and entry into the amyloid fibrillar state. Significantly, all of these responses are entirely resolved at much lower than the critical micellar concentration (CMC) of SDS. Electrostatic interaction of the dodecyl sulfate anion (DS- ) with positive surface potential on the protein can completely unfold both secondary and tertiary structures, which is followed by protein chain restructuration to α-helices. All SDS-denatured proteins contain more α-helices than the corresponding native state. SDS interaction stochastically drives proteins to the aggregated fibrillar state.
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Affiliation(s)
- Noorul Huda
- School of Chemistry, University of Hyderabad, Hyderabad, India
| | - Mujahid Hossain
- School of Chemistry, University of Hyderabad, Hyderabad, India
| | - Abani K Bhuyan
- School of Chemistry, University of Hyderabad, Hyderabad, India
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