The aim of this study was to investigate the effects of sodium dodecyl benzenesulfonate (SDBS) on hen egg white lysozyme (HEWL) fibrillogenesis at pH 7.4. HEWL fibrillogenesis in the presence of SDBS was characterized using several spectroscopic techniques (turbidity, light scattering, intrinsic fluorescence, ThT binding assay, ThT kinetics, far-UV CD, and transmission electron mmicroscopy). The turbidity and light scattering data revealed that SDBS induces aggregation in HEWL in dose-dependent manner. HEWL aggregation was seen at low SDBS concentrations (0.03 to 0.5 mM) but it was not observed at concentrations of SDBS at >0.6 mM. The ThT and TEM data clearly showed that the aggregates formed in the presence of SDBS had an amyloid-like morphology. From the CD analysis it was clear that low SDBS concentrations decreases the α-helical content while the β-sheet content increased. As the SDBS concentration further increased, the α-helical content increased again. The ThT kinetics analysis revealed that the HEWL monomer directly converted into the amyloid fibril without lag phase. All the spectroscopic and microscopic results support the finding that low concentrations of SDBS stimulate fibrillogenesis in HEWL, and that no fibrillogenesis occurs at higher SDBS concentrations. © 2019 Elsevier B.V.

Priyankar Sen

Centre for Bio-Separation and Technology

Vellore Campus

Khan J.M

Malik A

Ahmed A

Ahmed M

Alamery S.F

Almaharfi H.A

Choudhry H

Khan M.I.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

International Journal of Biological Macromolecules

Although many reports have described protein–surfactant interactions but the mechanism of amyloid-like fibril formation by surfactants is not clear. In this study, we investigated the role of sodium dodecylbenzene sulfonate (SDBS) to induce aggregation in equine heart muscle myoglobin (E–Mb) at pH 4.5. The aggregation was analyzed by Rayleigh scattering (RLS), turbidity, Thioflavin-T binding (ThT), and Congo red (CR) binding, circular dichroism spectroscopy and transmission electron microscopy (TEM). Turbidity and RLS analysis demarcated the aggregate were formed at effective range of SDBS concentration at pH 4.5, this led to the observation that at low concentrations (0.05 mM–1.2 mM) SDBS cause aggregation of E–Mb monomers, in contrast at higher SDBS concentrations the aggregates were not formed. The following observations were further supported through ThT and CR binding results suggests that SDBS-induced E–Mb aggregates have amyloid-like structure. Far-UV CD results for aggregated E–Mb also displayed single negative peak between 222−235 nm, which is a characteristic of cross-β-sheet. However, in the presence of high concentration of SDBS, the non-aggregated state of E–Mb obtained consisted of mixed α-helices and β-sheets. SDBS-induced aggregates had amyloid-like morphology as confirmed by TEM. These results indicate that both electrostatic forces and hydrophobic interactions contribute towards SDBS-induced E–Mb aggregates formation with a characteristic amyloid-like structure. Also, these findings have significant implications for understanding mechanisms underlying amyloid fibril formation by anionic surfactants. © 2019 Elsevier B.V.

Colloids and Surfaces A: Physicochemical and Engineering Aspects

Pre-micellar concentrations of sodium dodecylbenzene sulphonate induce amyloid-like fibril formation in myoglobin at pH 4.5

Chemistry and Physics of Lipids

Interaction of the β amyloid – Aβ(25–35) – peptide with zwitterionic and negatively charged vesicles with and without cholesterol

Journal of Chemical Sciences

Evaluation of micellar properties of sodium dodecylbenzene sulphonate in the presence of some salts

Negatively charged food additive dye “Allura Red” rapidly induces SDS-soluble amyloid fibril in beta-lactoglobulin protein

Effect of natural biopolymers on amyloid fibril formation and morphology

Nature Chemical Biology

Nucleation and growth of a bacterial functional amyloid at single-fiber resolution

Different conformational states of hen egg white lysozyme formed by exposure to the surfactant of sodium dodecyl benzenesulfonate

Journal	Data powered by TypesetInternational Journal of Biological Macromolecules
Publisher	Data powered by TypesetElsevier BV
ISSN	0141-8130
Open Access	0