FT-IR and Near-Infared FT-Raman Studies of the Secondary Structure of Insulinotropin in the Solid State: α-Helix to β-Sheet Conversion Induced by Phenol and/or by High Shear Force

1994 ◽  
Vol 83 (8) ◽  
pp. 1175-1180 ◽  
Author(s):  
Yesook Kim ◽  
Carol A. Rose ◽  
Yongliang Liu ◽  
Yukihiro Ozaki ◽  
Geeta Datta ◽  
...  
Keyword(s):  
Solid State ◽  
Secondary Structure ◽  
Shear Force ◽  
High Shear ◽  
Ft Ir ◽  
Α Helix ◽  
Β Sheet ◽  
Ft Raman

Multicomponent Peak Modeling of Protein Secondary Structures: Comparison of Gaussian with Lorentzian Analytical Methods for Plant Feed and Seed Molecular Biology and Chemistry Research

2005 ◽  
Vol 59 (11) ◽  
pp. 1372-1380 ◽  
Author(s):  
Peiqiang Yu
Keyword(s):  
Secondary Structure ◽  
Nutritive Value ◽  
Secondary Structures ◽  
Plant Seed ◽  
Relative Percentage ◽  
Protein Secondary Structures ◽  
Ft Ir ◽  
Ir Microspectroscopy ◽  
Α Helix ◽  
Β Sheet

The objective of this study was to compare Gaussian and Lorentzian multicomponent peak modeling methods in quantification of protein secondary structures of various plant seed and feed tissues within intact tissue at a cellular and subcellular level using the advanced synchrotron light sourced Fourier transform infrared (FT-IR) microspectroscopy (S-FTIR). This experiment was performed at the beamline U10B at the National Synchrotron Light Source (NSLS) in Brookhaven National Laboratory (BNL), U.S. Dept of Energy (NSLS-BNL, NY). The results show that in the comparison of the Gaussian and Lorentzian multi-peak modeling methods, the Gaussian method is more accurate for fitting multi-peak curves of protein secondary structures than the Lorentzian method, with higher modeling R2 values (0.92 versus 0.89, P < 0.05). There were no large differences ( P > 0.05) in the quantification of the relative percentage of α-helices, β-sheets, and others in protein secondary structures of the plant seed tissues, with averages of 30.2%, 40.4%, and 29.4%, respectively. However, there are significant differences ( P < 0.05) in the quantification of the ratios of β-sheet to α-helix (1.42 versus 1.60; SEM = 0.058) in protein secondary structures of the plant seed tissues. With synchrotron FT-IR microspectroscopy, the ultrastructural–chemical makeup and nutritive characteristics could be revealed at a high spatial resolution. Synchrotron-based FT-IR microspectroscopy revealed that the secondary structure of protein differed between the plant seed tissues in terms of relative percentage and ratio of protein secondary structures (α-helix and β-sheet) within cellular dimensions. The results also show that the flaxseed tissues contained higher ( P < 0.05) percentage of α-helix (38.6 versus 24.0%) and β-sheet (45.3 versus 36.9%), lower ( P < 0.05) percentage of other secondary structures (16.1% versus 39.0%), and higher ( P < 0.05) ratios of α-helix to β-sheet (0.90 versus 0.69) than the winterfat seed tissues. It must be mentioned that the relative percentages of protein secondary structure may not reflect the true secondary structure. However, the purpose of modeling the relative percentage of secondary structure was to detect the variety of differences among seed/feed/plant tissues and their relation to nutritive value and digestive behavior. The results demonstrate the potential of highly spatially resolved synchrotron-based FT-IR microspectroscopy to reveal protein secondary structures of the plant seed/feed tissues. Further study is needed to quantify the relationship between protein secondary structures and nutrient availability and digestive behavior of various varieties of plant seed tissues. Information from the infrared probing of protein secondary structures can be valuable as a guide to maintaining protein nutritive value and quality for animal and human use.

A Study of the Amide III Band by FT-IR Spectrometry of the Secondary Structure of Albumin, Myoglobin, and γ-Globulin

1987 ◽  
Vol 41 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Koichi Kaiden ◽  
Tomoko Matsui ◽  
Shigeyuki Tanaka
Keyword(s):  
Secondary Structure ◽  
Conformational Changes ◽  
Phosphate Buffer Solution ◽  
Heat Denaturation ◽  
Buffer Solution ◽  
Ir Spectrometry ◽  
Ft Ir ◽  
Α Helix ◽  
Β Lactoglobulin ◽  
Β Sheet

FT-IR spectrometry was applied to the identification of the secondary structure species of a living protein. The spectra of native myoglobin and albumin were obtained with methods using either KBr pellet or film formed on a KBr window from an aqueous solution. Pellet preparation of myoglobin and albumin caused the structure to change from α-helix to β-structure. The conformational changes that arise from heat denaturation of myoglobin, albumin, and γ-globulin were observed by the changes in the amide I, II, and III bands. The bands of the 1300, 1260, and 1235 cm−1 regions were respectively assigned to α-helix, disordered, and β-sheet structures. These band positions were substantiated by the spectra of β-lactoglobulin and α-casein. α-Helix structure probably changes to β-structure in the presence of alkali halide, and changes to disordered structure with heat denaturation in phosphate buffer solution. The secondary structure of a protein is further identified by use of the information obtained from the amide I, II, and III bands; the amide III band is especially important. Furthermore, it may be possible to characterize the species of secondary structures of proteins adsorbed on material surfaces.

Use of synchrotron-based FTIR microspectroscopy to determine protein secondary structures of raw and heat-treated brown and golden flaxseeds: A novel approach

2005 ◽  
Vol 85 (4) ◽  
pp. 437-448 ◽  
Author(s):  
P. Yu ◽  
J. J. McKinnon ◽  
H. W. Soita ◽  
C. R. Christensen ◽  
D. A. Christensen
Keyword(s):  
Secondary Structure ◽  
Matrix Protein ◽  
Protein Secondary Structure ◽  
Secondary Structures ◽  
Heat Processing ◽  
Lower Percentage ◽  
Protein Secondary Structures ◽  
Novel Approach ◽  
Α Helix ◽  
Β Sheet

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

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

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.

scholarly journals Prion Interaction with Normal Protein in Topological Changing Secondary Structure to Aggregation

2020 ◽  
Vol 9 (2) ◽  
pp. 53
Author(s):  
Yao Yao
Keyword(s):  
Hydrogen Bond ◽  
Secondary Structure ◽  
Amyloid Fibril ◽  
Double Helix ◽  
Β Amyloid ◽  
Structural Analogy ◽  
Β Sheets ◽  
Α Helix ◽  
Dna Double Helix ◽  
Β Sheet

<p>Prion is a protein smaller than virus and it infects host in the absence of nucleic acid. The secondary structure of protein folds incorrectly from α-helices to β-sheets through breaking and re-formation of hydrogen bond. Structural analogy of α-helix and DNA double helix and comparing differences between α-helix and β-sheet show prion's infectivity and propagation. Aggregates of dimers and polymers generate β-amyloid fibril in Alzheimer's disease.</p>

Phospholipid-Specific Conformational Changes in Human Prothrombin upon Binding to Procoagulant Acidic Lipid Membranes

1994 ◽  
Vol 71 (05) ◽  
pp. 596-604 ◽  
Author(s):  
Jogin R Wu ◽  
Barry R Lentz
Keyword(s):  
Secondary Structure ◽  
Conformational Changes ◽  
Lipid Membranes ◽  
Membrane Vesicles ◽  
Scanning Calorimetry ◽  
Domain Organization ◽  
Α Helix ◽  
Β Sheet ◽  
Prothrombin Activation

SummaryThis paper provides evidence to demonstrate that human prothrombin undergoes conformational changes upon binding to procoagulant membranes specifically containing phosphatidylserine (PS). Fourier transform infrared spectroscopy was used to show a slight increase in ordered (α-helix, β-sheet, β-turns) secondary structure upon binding to PS-containing membranes. Thermograms representing prothrombin and prothrombin fragment 1 denaturation were obtained using differential scanning calorimetry. These were analyzed and interpreted in terms of changes in prothrombin domain organization associated with binding to PS-containing membranes. Changes in either secondary structure or domain organization upon binding to negatively-charged phosphatidylglycerol-containing membranes were, if they occurred at all, much less dramatic. The results paralleled results obtained previously with bovine prothrombin (1, 2). The implications of these results in terms of a possible molecular mechanism for the cofactor-like role of platelet membrane vesicles in prothrombin activation are discussed.

What vibrations tell about proteins

2002 ◽  
Vol 35 (4) ◽  
pp. 369-430 ◽  
Author(s):  
Andreas Barth ◽  
Christian Zscherp
Keyword(s):  
Amino Acid ◽  
Secondary Structure ◽  
Ir Spectroscopy ◽  
Reaction Mechanisms ◽  
Amino Acid Side Chain ◽  
Difference Spectroscopy ◽  
Transition Dipole ◽  
Dipole Coupling ◽  
Α Helix ◽  
Β Sheet

1. Introduction 3702. Infrared (IR) spectroscopy – general principles 3722.1 Vibrations 3722.2 Information that can be derived from the vibrational spectrum 3722.3 Absorption of IR light 3753. Protein IR absorption 3763.1 Amino-acid side-chain absorption 3763.2 Normal modes of the amide group 3814. Interactions that shape the amide I band 3824.1 Overview 3824.2 Through-bond coupling 3834.3 Hydrogen bonding 3834.4 Transition dipole coupling (TDC) 3835. The polarization and IR activity of amide I modes 3875.1 The coupled oscillator system 3875.2 Optically allowed transitions 3885.3 The infinite parallel β-sheet 3885.4 The infinite antiparallel β-sheet 3895.5 The infinite α-helix 3906. Calculation of the amide I band 3916.1 Overview 3916.2 Perturbation treatment by Miyazawa 3936.3 The parallel β-sheet 3946.4 The antiparallel β-sheet 3956.5 The α-helix 3966.6 Other secondary structures 3987. Experimental analysis of protein secondary structure 3987.1 Band fitting 3987.2 Methods using calibration sets 4017.3 Prediction quality 4038. Protein stability 4048.1 Thermal stability 4048.2 1H/2H exchange 4069. Molecular reaction mechanisms of proteins 4089.1 Reaction-induced IR difference spectroscopy 4089.2 The origin of difference bands 4099.3 The difference spectrum seen as a fingerprint of conformational change 4109.4 Molecular interpretation: strategies of band assignment 41610. Outlook 41911. Acknowledgements 42012. References 420This review deals with current concepts of vibrational spectroscopy for the investigation of protein structure and function. While the focus is on infrared (IR) spectroscopy, some of the general aspects also apply to Raman spectroscopy. Special emphasis is on the amide I vibration of the polypeptide backbone that is used for secondary-structure analysis. Theoretical as well as experimental aspects are covered including transition dipole coupling. Further topics are discussed, namely the absorption of amino-acid side-chains, 1H/2H exchange to study the conformational flexibility and reaction-induced difference spectroscopy for the investigation of reaction mechanisms with a focus on interpretation tools.

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