Kinetic Aspects of Surfactant-Induced Structural Changes of Proteins－Unsolved Problems of Two-State Model for Protein Denaturation－

Takeda, Kazuhiko; Moriyama, Yoshiko

doi:10.5650/jos.ess15157

Cited by 8 publications

(20 citation statements)

References 57 publications

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“…The observations described above seem consistent with the views of Takeda and Moriyama 3 that there are no free protein molecules in solutions containing proteins and SDS regardless of the surfactant concentration and that the protein binding processes for SDS are virtually irreversible.…”

Section: Results and Discussionsupporting

confidence: 89%

“… 1 − 9 Sodium dodecyl sulfate (SDS), an anionic detergent known to unfold globular proteins, is most commonly used in these studies as a representative surfactant. 2 , 3 , 10 , 11 …”

Section: Introductionmentioning

confidence: 99%

“…The research described in this paper tackles problems related to the free protein fraction in the presence of SDS, reversibility of protein–SDS binding, and reversibility of changes induced by SDS in protein structures that thus far have not been fully explained. 3 …”

Section: Introductionmentioning

confidence: 99%

“…These changes are related to distinct protein–SDS complexes. According to Takeda and Moriyama, 3 there are specific numbers of surfactant molecules that the protein can form complexes with. Therefore, there are certain threshold SDS concentration values corresponding to different numbers of surfactant molecules bound by each protein.…”

Section: Introductionmentioning

confidence: 99%

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Circular Dichroism Spectra of α-Chymotrypsin–SDS Solutions Depend on the Procedure of Their Preparation

et al. 2022

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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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Section: Results and Discussionsupporting

confidence: 89%

“… 1 − 9 Sodium dodecyl sulfate (SDS), an anionic detergent known to unfold globular proteins, is most commonly used in these studies as a representative surfactant. 2 , 3 , 10 , 11 …”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Circular Dichroism Spectra of α-Chymotrypsin–SDS Solutions Depend on the Procedure of Their Preparation

et al. 2022

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“…Work on the influence of SDS in protein folding and metal ion binding, thermodynamics and kinetics of protein‐surfactant interactions and forces involved therein, and the complexity of changes brought about in the protein structure, has been carried out. Nevertheless, questions remain, including the structure of the SDS‐protein complex, the resistance of β‐sheet proteins to denaturation, shifting and restructuration of β → α secondary structures, the role of electrostatic vs hydrophobic interactions in altering the conformational landscape, and the SDS‐to‐protein ratio‐dependent aggregation of the complex . The difficulties arise partly from the protein‐specific SDS‐resistance, termed kinetic stability, anomalous SDS effects, and the strong binding of the ionic surfactant to protein side chains, which allows only a narrow window in the submillimolar concentration for experimental work.…”

Section: Introductionmentioning

confidence: 99%

Complete observation of all structural, conformational, and fibrillation transitions of monomeric globular proteins at submicellar sodium dodecyl sulfate concentrations

2019

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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. K E Y W O R D S amyloid fibrillation, protein-SDS interactions, SDS denaturation, SDS unfolding 1 | INTRODUCTIONThe wide range of applications of the sodium dodecyl sulfate (SDS)protein system, including a fundamental understanding of molecular structures in micelle mimetics of membranes [1] and industrial production of washes and hygiene products, has led to numerous studies on it. Work on the influence of SDS in protein folding [2] and metal ion binding, [3] thermodynamics and kinetics of proteinsurfactant interactions [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and forces involved therein, [21,22] and the complexity of changes brought about in the protein structure, [17,18,23,24] has been carried out. Nevertheless, questions remain, including the structure of the SDS-protein complex, the resistance of β-sheet proteins to denaturation, [6,11] shifting and restructuration of β ! α secondary structures, [22,25] the role of electrostatic vs hydrophobic interactions in altering the conformational landscape, [24] and the SDS-to-protein ratio-dependent aggregation of the complex. [5] The difficulties arise partly from the protein-specific SDS-resistance, termed kinetic stability, [6] anomalous SDS effects, [26] and the strong binding of the ionic surfactant to protein side chains, which allows only a narrow window in the submillimolar concentration for experimental work. For example, guanidinium hydrochloride which binds weakly to proteins is needed at molar concentrations to denature proteins, but substantial changes in the structure and conformation of proteins already take place at micromolar concentrations of SDS. [16] This study aims to provide a unified conceptual understanding of the action of SDS on protein structures and conformation with reference to the surfactant-binding isotherm and possible modes of binding. Experiments have been performed with six proteins: lysozyme, cytochrome c, myoglobin, α-lactalbumin, ...

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Techniques for Protein Analysis

Büyükköroğlu

Dora

Özdemir

et al. 2018

Omics Technologies and Bio-Engineering

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Kinetic Aspects of Surfactant-Induced Structural Changes of Proteins－Unsolved Problems of Two-State Model for Protein Denaturation－

Cited by 8 publications

References 57 publications

Circular Dichroism Spectra of α-Chymotrypsin–SDS Solutions Depend on the Procedure of Their Preparation

Circular Dichroism Spectra of α-Chymotrypsin–SDS Solutions Depend on the Procedure of Their Preparation

Complete observation of all structural, conformational, and fibrillation transitions of monomeric globular proteins at submicellar sodium dodecyl sulfate concentrations

Techniques for Protein Analysis

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