Faculty Opinions recommendation of Parallel β-sheet secondary structure is stabilized and terminated by interstrand disulfide cross-linking.

The objectives of the study were to use synchrotron Fourier transform infrared microspectroscopy (S-FTIR) as a novel approach to: (1) reveal ultra-structural chemical features of protein secondary structures of flaxseed tissues affected by variety (golden and brown) and heat processing (raw and roasted), and (2) quantify protein secondary structures using Gaussian and Lorentzian methods of multi-component peak modeling. By using multi-component peak modeling at protein amide I region of 1700–1620 cm-1, the results showed that the golden flaxseed contained relatively higher percentage of α-helix (47.1 vs. 36.9%), lower percentage of β-sheet (37.2 vs. 46.3%) and higher (P < 0.05) ratio of α-helix to β-sheet than the brown flaxseed (1.3 vs. 0.8). The roasting reduced (P < 0.05) percentage of α-helix (from 47.1 to 36.1%), increased percentage of β-sheet (from 37.2 to 49.8%) and reduced α-helix to β-sheet ratio (1.3 to 0.7) of the golden flaxseed tissues. However, the roasting did not affect percentage and ratio of α-helix and β-sheet in the brown flaxseed tissue. No significant differences were found in quantification of protein secondary structures between Gaussian and Lorentzian methods. These results demonstrate the potential of highly spatially resolved S-FTIR to localize relatively pure protein in the tissue and reveal protein secondary structures at a cellular level. The results indicated relative differences in protein secondary structures between flaxseed varieties and differences in sensitivities of protein secondary structure to the heat processing. Further study is needed to understand the relationship between protein secondary structure and protein digestion and utilization of flaxseed and to investigate whether the changes in the relative amounts of protein secondary structures are primarily responsible for differences in protein availability. Key words: Synchrotron, FTIR microspectrosopy, flaxseeds, intrinsic structural matrix, protein secondary structures, protein nutritive value

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Two-Dimensional Infrared Spectroscopy of Antiparallel β-Sheet Secondary Structure

Journal of the American Chemical Society ◽

10.1021/ja049811j ◽

2004 ◽

Vol 126 (25) ◽

pp. 7981-7990 ◽

Cited By ~ 169

Author(s):

Nurettin Demirdöven ◽

Christopher M. Cheatum ◽

Hoi Sung Chung ◽

Munira Khalil ◽

Jasper Knoester ◽

...

Keyword(s):

Infrared Spectroscopy ◽

Secondary Structure ◽

Two Dimensional ◽

Two Dimensional Infrared Spectroscopy ◽

Β Sheet

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Lamellar mesoscopic organization of supramolecular polymers: a necessary pre-ordering secondary structure

Polymer Chemistry ◽

10.1039/c7py01219e ◽

2017 ◽

Vol 8 (38) ◽

pp. 5954-5961 ◽

Cited By ~ 6

Author(s):

J. Lacombe ◽

C. Soulié-Ziakovic

Keyword(s):

Secondary Structure ◽

Supramolecular Polymers ◽

Β Sheet

Thy-functionalized PPGs organize in lamellae due to the alignment of amide links in a β-sheet-like secondary structure analogous to proteins.

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(De)stabilization of Alpha-Synuclein Fibrillary Aggregation by Charged and Uncharged Surfactants

International Journal of Molecular Sciences ◽

10.3390/ijms222212509 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12509

Author(s):

Joana Angélica Loureiro ◽

Stéphanie Andrade ◽

Lies Goderis ◽

Ruben Gomez-Gutierrez ◽

Claudio Soto ◽

...

Keyword(s):

Secondary Structure ◽

Hydrophobic Interactions ◽

Neurodegenerative Disorder ◽

Sodium Dodecyl ◽

Lewy Bodies ◽

Alpha Synuclein ◽

Cetyltrimethylammonium Chloride ◽

Α Helix ◽

Β Sheet

Parkinson’s disease (PD) is the second most common neurodegenerative disorder. An important hallmark of PD involves the pathological aggregation of proteins in structures known as Lewy bodies. The major component of these proteinaceous inclusions is alpha (α)-synuclein. In different conditions, α-synuclein can assume conformations rich in either α-helix or β-sheets. The mechanisms of α-synuclein misfolding, aggregation, and fibrillation remain unknown, but it is thought that β-sheet conformation of α-synuclein is responsible for its associated toxic mechanisms. To gain fundamental insights into the process of α-synuclein misfolding and aggregation, the secondary structure of this protein in the presence of charged and non-charged surfactant solutions was characterized. The selected surfactants were (anionic) sodium dodecyl sulphate (SDS), (cationic) cetyltrimethylammonium chloride (CTAC), and (uncharged) octyl β-D-glucopyranoside (OG). The effect of surfactants in α-synuclein misfolding was assessed by ultra-structural analyses, in vitro aggregation assays, and secondary structure analyses. The α-synuclein aggregation in the presence of negatively charged SDS suggests that SDS-monomer complexes stimulate the aggregation process. A reduction in the electrostatic repulsion between N- and C-terminal and in the hydrophobic interactions between the NAC (non-amyloid beta component) region and the C-terminal seems to be important to undergo aggregation. Fourier transform infrared spectroscopy (FTIR) measurements show that β-sheet structures comprise the assembly of the fibrils.

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Time evolution of β-lactoglobulin corona formation on gold nanoparticles and impact on allergy

10.21203/rs.2.23072/v1 ◽

2020 ◽

Author(s):

Xiaoning Zhang ◽

Meifeng Li ◽

Yuanping Lv ◽

Xiaoling Sun ◽

Yao Han ◽

...

Keyword(s):

Gold Nanoparticles ◽

Secondary Structure ◽

Time Evolution ◽

Electrostatic Force ◽

Protein Corona ◽

Raw Milk ◽

Covalent Bonds ◽

Corona Formation ◽

Β Lactoglobulin ◽

Β Sheet

Abstract Gold nanoparticles (AuNPs) are modified immediately by the adsorption of β-lactoglobulin (βlg) when designed as colorimetric probe in raw milk, leading to the formation of a protein corona. This adsorption results mainly from a fast electrostatic force and a slow formation of Au-S covalent bonds, which is a precondition for the use of AuNPs in biodetection. The proteins corona influences the structure and bioactivity of adsorbed protein, such as the allergy. In this study, the mechanism of βlg adsorbed on AuNPs was investigated in terms of stoichiometry, binding affinity (Ka), time evolution of Au-S bond, and general secondary structure changes to address the desensitization of AuNPs. The results show that about 3,600 βlg are adsorbed on a single AuNPs, and the Ka is 2.9 ± 0.7 × 10 6 M -1 . The formation of Au-S bonds takes about 9 h, which is the time needed for complete changes in secondary structure and the IgE combining capacity. The structure of allergenic epitopes assigned to β-sheet was destroyed by the formation of Au-S bond, then induced to the decrease allergy. Furthermore, Fourier transform infrared spectroscopy confirmed a decrease in β-sheet contents after conjugated with AuNPs.

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